chore(go): tweak runtime publishing artifacts

- Make LICENSE be the **verbatim** Apache 2.0 license text
- Re-flow `RUNTIME.md` and `CONTRIBUTING.md`, and standardize appearance
  as well as `jsii` capitalization.
- Add a `.gitattributes` for correct GitHub LOC statistics, etc...

packages/@jsii/go-runtime/jsii-runtime-go/.gitattributes

@@ -0,0 +1,5 @@
+*.generated.go linguist-generated
+*.generated_test.go linguist-generated
+*.tgz linguist-generated
+
+doc.go linguist-documentation

packages/@jsii/go-runtime/jsii-runtime-go/CONTRIBUTING.md

@@ -1 +1,6 @@
-The go JSII runtime source code is managed in [the main JSII repository](https://github.com/aws/jsii). See the [contributing](https://github.com/aws/jsii/blob/main/CONTRIBUTING.md) guide for details on filing issues and PRs.
+The jsii runtime library for go's source code is managed in the
+[main jsii repository][jsii]. See the [contributing] guide for details on filing
+issues and PRs.
+
+[jsii]: https://github.com/aws/jsii
+[contributing]: https://github.com/aws/jsii/blob/main/CONTRIBUTING.md

packages/@jsii/go-runtime/jsii-runtime-go/LICENSE

@@ -187,7 +187,7 @@
  same "printed page" as the copyright notice for easier
  identification within third-party archives.
 
- Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ Copyright [yyyy] [name of copyright owner]
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -199,4 +199,4 @@
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
- limitations under the License.
+ limitations under the License.

packages/@jsii/go-runtime/jsii-runtime-go/README.md

@@ -1,3 +1,19 @@
-# JSII Go Runtime
+# ![jsii](https://github.com/aws/jsii/raw/main/logo/png/128.png)
 
-This is the JSII runtime for go. This repository is used only for publishing the go module. The source code is managed in [the main JSII repository](https://github.com/aws/jsii). Refer to the [go-runtime readme there](https://github.com/aws/jsii/blob/main/packages/%40jsii/go-runtime/README.md) for details on building and testing the module.
+## The jsii runtime library for Go
+
+This is the [jsii] runtime for go. This repository is used only for publishing
+the go module. The source code is managed in [the main JSII repository][jsii].
+Refer to the [go-runtime readme there][readme] for details on building and
+testing the module.
+
+[jsii]: https://github.com/aws/jsii
+[readme]: https://github.com/aws/jsii/blob/main/packages/%40jsii/go-runtime/README.md
+
+## :balance_scale: License
+
+**jsii** is distributed under the [Apache License, Version 2.0][apache-2.0].
+
+See [LICENSE](./LICENSE) and [NOTICE](./NOTICE) for more information.
+
+[apache-2.0]: https://www.apache.org/licenses/LICENSE-2.0