Based on work by @AArnott in dotnet/roslyn-sdk#240

Fixes #34678

the cancellation token will be removed from ICodeCleanUpFixer in next API update

* Fixes #34684

* Change from .Net to .NET

* update xlf files

* Remove InteractiveHost dependency from nuget packages

* Fix Newtonsoft.Json ambiguity

Fix wrong package name for VS debugger

TempPE compiler fixes

Simplify handling of 'enter' in formatting.

Don't complete statement on element access expression unless caret is inside bracketed argument list (#34706)

* Fixes #34666

* Update CompleteStatementCommandHandler.cs

Fix unconditional binding of pointer types

Use correct Solution snapshot in call to UpdateSolutionForBatch

Move to namespace UI and Implementation

Export CodeCleanUpFixerProvider rather than register it

Remove workaround for automatic line ender with async completion

Merge dev16.1-preview1 to master

Support `inlineDescription` parameter for `AssertSelectedCompletionItem` in ModernCompletionTestState (#34689)

Fix commit tests

Remove unnecessary StreamJsonRpc reference

The editor now handles this command, so our workaround became dead code
in 16.0 RTM.

The VsDebugPresentationPackage does not follow the same
naming convention as the other packages. So the previous name
is wrong.

Disallow declaration of static members in interfaces when target runtime doesn’t support Default Interface Methods. (#34682)

Fixes #34590.

Features/readonly members

This reverts commit b6285348.

* Add IsDeclaredReadOnly and IsEffectivelyReadOnly to public API

* Fix build. Add simple SemanticModel test.

* Fix Roslyn users of IMethodSymbol. Expand semantic model test.

* Fix visibility of MethodSymbol.vb members

* Implement ReadOnly method API in CodeGenerationConstructedMethodSymbol

* Cleanup usings and change NotImplementedException to ExceptionUtilities.Unreachable

* Simplify down to IMethodSymbol.IsReadOnly

* Fix IsReadOnly API for reduced extension methods. Test ref readonly ref
properties.

* Ensure that non-reduced extension methods are never 'readonly'

* Update doc

* Reduced extension methods are not declared readonly, they're effectively readonly.

* Remove unused copy of extension methods test source

Merge master to features/readonly-members

Merge master to features/readonly-members