[Feature Request] Add doc comments and include to NuGet package

[filzrev]

Currently published NuGet package don't contains documentation XML file.
So intellisense is not works when using NuGet package.

I thought following tasks are needed as future tasks.

1. Add documentation comment that based on LINQ methods.

2. Add <inheritdoc /> tags

3. Add additional <remark> tags (e.g. Enumerator/GetEnumerator() should be disposed. When enumerated manually)

4. And publish doc XML files with following setting.

   <GenerateDocumentationFile>true</GenerateDocumentationFile>

[neuecc]

Thank you, I've temporarily implemented just the GenerateDocumentFile.
I'll do details later...