linting: Restore code generation checks

[gdavison]

Restores linting for generated code, updates documentation, and removes unneeded exports

Relates #20000

[ewbankkit]

Need to add cd tools && go install golang.org/x/tools/cmd/goimports to the tools target, else

% make gen
rm -f internal/service/**/*_gen.go
go generate ./...
goimports -w ./internal
make: goimports: No such file or directory
make: *** [gen] Error 1

% cd tools && go install golang.org/x/tools/cmd/goimports
% goimports -w ./internal

[ewbankkit]

LGTM 🚀.

[zhelding]

Pull request #21306 has significantly refactored the AWS Provider codebase. As a result, most PRs opened prior to the refactor now have merge conflicts that must be resolved before proceeding.

Specifically, PR #21306 relocated the code for all AWS resources and data sources from a single aws directory to a large number of separate directories in internal/service, each corresponding to a particular AWS service. This separation of code has also allowed for us to simplify the names of underlying functions -- while still avoiding namespace collisions.

We recognize that many pull requests have been open for some time without yet being addressed by our maintainers. Therefore, we want to make it clear that resolving these conflicts in no way affects the prioritization of a particular pull request. Once a pull request has been prioritized for review, the necessary changes will be made by a maintainer -- either directly or in collaboration with the pull request author.

For a more complete description of this refactor, including examples of how old filepaths and function names correspond to their new counterparts: please refer to issue #20000.

For a quick guide on how to amend your pull request to resolve the merge conflicts resulting from this refactor and bring it in line with our new code patterns: please refer to our Service Package Refactor Pull Request Guide.

[github-actions]

This functionality has been released in v3.64.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

I'm going to lock this pull request because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.