[Enhancement] Include "Source Generators Cookbook" github markdown only page into deployed web html docs?

### Type of issue

Other (describe below)

### Description

Hey dotnet docs team!
I am looking for some Tutorials about how to start writing my first Source Generator and the only Web availabele docs, which are not "just" a md on github, are about writing Analyzers (which are outdated as issued already) and none e.g. in the TOC is about Source Generator itself 🤔

So I would like to suggest, to maybe include the "Source Generators Cookbook" you have linked in this Section:
- https://learn.microsoft.com/de-de/dotnet/csharp/roslyn-sdk/#source-generators

Included in the actual web available docs just like the Analyzers and add it (of course) to the TOC too 🚀

### Page URL

https://learn.microsoft.com/de-de/dotnet/csharp/roslyn-sdk/

### Content source URL

https://github.com/dotnet/docs/blob/main/docs/csharp/roslyn-sdk/index.md

### Document Version Independent Id

debed50c-98ce-ec0e-bcf6-0170a4e60fcc

### Platform Id

d2e13edd-6c59-3eb1-90a0-0090ef7a820e

### Article author

@BillWagner

### Metadata

* ID: e4bd716a-906d-983b-141c-4a4e2e2a79ec
* PlatformId: d2e13edd-6c59-3eb1-90a0-0090ef7a820e
* Service: **dotnet-csharp**
* Sub-service: **roslyn-sdk**

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