Add "where" clause information to C# docs

Description

In the LINQ section we should add how to to implement $elemMatch using Any.
This was present in old driver documention but it's not in new one.

Scope of changes

This has grown in scope to incorporate including where information that used to be present in older versions of the documentation.

The old content should be ported over as is after verification that it works.

Impact to Other Docs

MVP (Work and Date)

Resources (Scope or Design Docs, Invision, etc.)