feat(generate): Support multiple configuration example files in default templates (#511)

* feat(generate): Support multiple configuration example files in default templates

Reference: #508

This change updates the generate command to search for multiple configuration example files using a wildcard and render all found files with the default templates (e.g. `resource*.tf` instead of just `resource.tf`). Compatibility with the existing singular `HasExample` and `ExampleFile` fields for templating is preserved, while new plural `HasExamples` and `ExampleFiles` fields were added into the template data. The testing for this feature was added by duplicating the existing "no templates" txtar, then adding second configuration example files:

```diff
4c4
< # Successful run of tfplugindocs on a Framework provider with examples but no templates or pre-exiting docs.
---
> # Successful run of tfplugindocs on a Framework provider with multiple configuration examples but no templates or pre-exiting docs.
57c57
<   configurable_attribute = "some-value"
---
>   configurable_attribute = "some-value1"
60a61,66
> ```terraform
> data "scaffolding_example" "example" {
>   configurable_attribute = "some-value2"
> }
> ```
>
91a98,103
> ```terraform
> output "test" {
>   value = provider::scaffolding::example("testvalue3", "testvalue4")
> }
> ```
>
122a135,140
> }
> ```
>
> ```terraform
> output "test" {
>   value = provider::scaffolding::no-variadic("testvalue2")
153c171
<   # example configuration here
---
>   # first example configuration here
156a175,180
> ```terraform
> provider "scaffolding" {
>   # second example configuration here
> }
> ```
>
180c204
<   configurable_attribute = "some-value"
---
>   configurable_attribute = "some-value1"
183a208,213
> ```terraform
> resource "scaffolding_example" "example" {
>   configurable_attribute = "some-value2"
> }
> ```
>
258c288
<   configurable_attribute = "some-value"
---
>   configurable_attribute = "some-value1"
261a292,297
> ```terraform
> resource "scaffolding_example" "example" {
>   configurable_attribute = "some-value2"
> }
> ```
>
285c321
<   configurable_attribute = "some-value"
---
>   configurable_attribute = "some-value1"
286a323,326
> -- examples/data-sources/scaffolding_example/data-source2.tf --
> data "scaffolding_example" "example" {
>   configurable_attribute = "some-value2"
> }
290a331,334
> -- examples/functions/example/function2.tf --
> output "test" {
>   value = provider::scaffolding::example("testvalue3", "testvalue4")
> }
294a339,342
> -- examples/functions/no-variadic/function2.tf --
> output "test" {
>   value = provider::scaffolding::no-variadic("testvalue2")
> }
297c345
<   # example configuration here
---
>   # first example configuration here
298a347,350
> -- examples/provider/provider2.tf --
> provider "scaffolding" {
>   # second example configuration here
> }
323c375
<   configurable_attribute = "some-value"
---
>   configurable_attribute = "some-value1"
324a377,380
> -- examples/resources/scaffolding_example/resource2.tf --
> resource "scaffolding_example" "example" {
>   configurable_attribute = "some-value2"
> }
327c383
<   configurable_attribute = "some-value"
---
>   configurable_attribute = "some-value1"
329c385,388
<
---
> -- examples/ephemeral-resources/scaffolding_example/ephemeral-resource2.tf --
> resource "scaffolding_example" "example" {
>   configurable_attribute = "some-value2"
> }
```

* test fix after recent merge

* fix merge conflict

---------

Co-authored-by: Austin Valle <austinvalle@gmail.com>

Author: bflad

.changes/unreleased/FEATURES-20250819-133400.yaml

@@ -0,0 +1,5 @@
+kind: FEATURES
+body: 'generate: Support multiple configuration example files in default templates'
+time: 2025-08-19T13:34:00.429551-04:00
+custom:
+    Issue: "508"

README.md

@@ -226,18 +226,18 @@ For examples:
 > **NOTE:** In the following conventional paths for examples, `<data source name>` and `<resource name>` include the provider prefix as well, but the provider prefix is **NOT** included in`<function name>`.
 > For example, the data source [`caller_identity`](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/caller_identity) in the `aws` provider would have an "example" conventional path of: `examples/data-sources/aws_caller_identity/data-source.tf`
 
-| Path                                                                      | Description                                |
-|---------------------------------------------------------------------------|--------------------------------------------|
-| `examples/`                                                               | Root of examples                           |
-| `examples/provider/provider.tf`                                           | Provider example config                    |
-| `examples/actions/<action_type>/action.tf`                                | Action example config                      |
-| `examples/data-sources/<data source name>/data-source.tf`                 | Data source example config                 |
-| `examples/ephemeral-resources/<ephemeral resource>/ephemeral-resource.tf` | Ephemeral resource example config          |
-| `examples/functions/<function name>/function.tf`                          | Function example config                    |
-| `examples/resources/<resource name>/resource.tf`                          | Resource example config                    |
-| `examples/resources/<resource name>/import.sh`                            | Resource example import command            |
-| `examples/resources/<resource name>/import-by-string-id.tf`               | Resource example import by id config       |
-| `examples/resources/<resource name>/import-by-identity.tf`                | Resource example import by identity config |
+| Path                                                                         | Description                                |
+|------------------------------------------------------------------------------|--------------------------------------------|
+| `examples/`                                                                  | Root of examples                           |
+| `examples/provider/provider<*>.tf`                                           | Provider example config(s)                 |
+| `examples/actions/<action_type>/action.tf`                                   | Action example config                      |
+| `examples/data-sources/<data source name>/data-source<*>.tf`                 | Data source example config(s)              |
+| `examples/ephemeral-resources/<ephemeral resource>/ephemeral-resource<*>.tf` | Ephemeral resource example config(s)       |
+| `examples/functions/<function name>/function<*>.tf`                          | Function example config(s)                 |
+| `examples/resources/<resource name>/resource<*>.tf`                          | Resource example config(s)                 |
+| `examples/resources/<resource name>/import.sh`                               | Resource example import command            |
+| `examples/resources/<resource name>/import-by-string-id.tf`                  | Resource example import by id config       |
+| `examples/resources/<resource name>/import-by-identity.tf`                   | Resource example import by identity config |
 
 #### Migration
 
@@ -291,8 +291,10 @@ using the following data fields and functions:
 | Field                   | Type   | Description                                                                               |
 |-------------------------|--------|-------------------------------------------------------------------------------------------|
 | `.Description`          | string | Provider description                                                                      |
-| `.HasExample`           | bool   | Is there an example file?                                                                 |
-| `.ExampleFile`          | string | Path to the file with the terraform configuration example                                 |
+| `.HasExample`           | bool   | (Legacy) Is there an example file?                                                        |
+| `.HasExamples`          | bool   | Are there example files? Always true if HasExample is true.                               |
+| `.ExampleFile`          | string | (Legacy) Path to the file with the Terraform configuration example.                       |
+| `.ExampleFiles`         | string | Paths to the files with the Terraform configuration example. Includes ExampleFile.        |
 | `.ProviderName`         | string | Canonical provider name (ex. `terraform-provider-random`)                                 |
 | `.ProviderShortName`    | string | Short version of the rendered provider name (ex. `random`)                                |
 | `.RenderedProviderName` | string | Value provided via argument `--rendered-provider-name`, otherwise same as `.ProviderName` |
@@ -305,8 +307,10 @@ using the following data fields and functions:
 | `.Name`                     | string | Name of the resource/data-source (ex. `tls_certificate`)                                   |
 | `.Type`                     | string | Either `Resource` or `Data Source`                                                         |
 | `.Description`              | string | Resource / Data Source description                                                         |
-| `.HasExample`               | bool   | Is there an example file?                                                                  |
-| `.ExampleFile`              | string | Path to the file with the terraform configuration example                                  |
+| `.HasExample`               | bool   | (Legacy) Is there an example file?                                                         |
+| `.HasExamples`              | bool   | Are there example files? Always true if HasExample is true.                                |
+| `.ExampleFile`              | string | (Legacy) Path to the file with the Terraform configuration example.                        |
+| `.ExampleFiles`             | string | Paths to the files with Terraform configuration examples. Includes ExampleFile.            |
 | `.HasImport`                | bool   | Is there an import shell file? (`terraform import` shell example)                          |
 | `.ImportFile`               | string | Path to the file with the command for importing the resource                               |
 | `.HasImportIDConfig`        | bool   | Is there an import terraform config file? (`import` block example with `id`)               |
@@ -327,8 +331,10 @@ using the following data fields and functions:
 |                             `.Type` | string | Returns `Function`                                                                        |
 |                      `.Description` | string | Function description                                                                      |
 |                          `.Summary` | string | Function summary                                                                          |
-|                       `.HasExample` |  bool  | Is there an example file?                                                                 |
-|                      `.ExampleFile` | string | Path to the file with the terraform configuration example                                 |
+|                       `.HasExample` |  bool  | (Legacy) Is there an example file?                                                        |
+|                      `.HasExamples` |  bool  | Are there example files? Always true if HasExample is true.                               |
+|                      `.ExampleFile` | string | (Legacy) Path to the file with the Terraform configuration example                        |
+|                     `.ExampleFiles` | string | Paths to the files with Terraform configuration examples. Includes ExampleFile.           |
 |                     `.ProviderName` | string | Canonical provider name (ex. `terraform-provider-random`)                                 |
 |                `.ProviderShortName` | string | Short version of the rendered provider name (ex. `random`)                                |
 |             `.RenderedProviderName` | string | Value provided via argument `--rendered-provider-name`, otherwise same as `.ProviderName` |