Move dependent-type-finding operations out of process.

Fix issue with linked files creating duplicate edits

Now that we have a work around for the VB runtime reference issue when
using the embedded option we can move MS.CA.VisualBasic to be
multi-targeted to `netcoreapp3.1` and `netstandard2.0` just as we do
for MS.CA.CSharp

Related: https://github.com/dotnet/sdk/issues/10591

Set xUnit1004 to hidden severity

⏱ Enable Server GC for FormatterBenchmarks

Add a hang mitigating timeout to CSharpBuild.BuildWithCommandLine

Make more dependent-type-finder operations public through SymbolFinder.

Bring the source gen docs up to date with what exists in master

Ensure that we can cancel during rename conflict detection.

Move convert tuple to struct oop

* Move RazorRemoteHostClient functionality to ExternalAccess.Razor

* Add file

Sometimes we do want the preview/provisional tab to receive focus. For example, when navigating to definition of a symbol and there's only one definition.

Fixes #43585

Co-Authored-By: NPhillip Carter <pcarter@fastmail.com>