`FSharpExpr` documentation references nonexistent module

[tymokvo]

trafficstars

The FSharpExpr type indicates that the active patterns for working with it are in the SourceCodeServices module.

https://github.com/dotnet/fsharp/blob/a4666e226f6f37c29128b37361175a52bf09c282/src/Compiler/Symbols/Exprs.fsi#L61

I believe this module was broken up into other namespaces as part of release 40.0.000.

https://github.com/dotnet/fsharp/blob/a4666e226f6f37c29128b37361175a52bf09c282/release-notes.md?plain=1#L122-L124

This should probably be replaced with a reference to FSharp.Compiler.Symbols.FSharpExprPatterns.