Support xmldoc `<inheritdoc>` and `<include>`

Pretty self-explanatory: it would be nice if the compiler supported [``](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/xmldoc/recommended-tags#inheritdoc) and [``](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/xmldoc/recommended-tags#include) elements in xmldoc contexts. The F# docs explicitly mention that this is not supported (see [here](https://learn.microsoft.com/en-us/dotnet/fsharp/language-reference/xml-documentation#limitations)), and I didn't find an issue already tracking this.