Fix for LSP diagnostic bugs

Activate language client during workspace load.

* Annotate NamespaceOrTypeSymbol

* Annotate public model for NamespaceOrTypeSymbol

* Add double checked locking for AdditionalTextFile.GetText.

* Use LazyInitializer

* Use Lazy instead of LazyInitializer

* Make _text readonly

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.20113.6

Merge release/dev16.5 to master

The changes made in https://github.com/dotnet/roslyn/pull/41123 fix the
GetHashCode for SubstitutedMethodSymbol for more nullability scenarios,
but end up hashing all generic methods with a non-generic containing
type into the same bucket. This can cause large performance regressions
for the compiler.

This change ensures that substituted symbols which have substitutions
equivalent to their original methods' type parameter continue to be
equal, but substituted methods with different type substitutions are not
considered equal.

Reduce the amount of stack space needed for parsing embedded statements

Enable NodeHasSyntacticErrors

Increase the amount of recursive parsing calls for statements+blocks.

Do not apply SuppressMessage suppressions to compiler diagnostics

Use less stack space while parsing if-statements

Revert compiler update that slowed down the build

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.20112.7

Merge release/dev16.5 to master

Use correct project capability for test projects

Don't attempt to provide a navbar if there is no navbar language serv…

Simplify error recovery for misplaced await-expressions.

Skip flaky Emit test

Merge release/dev16.5 to master

Add discord badge

This restores the compiler toolset from prior to #41575 to mitigate the
build performance regression.

Use syntax kinds in more cases.

Part of https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1065328