Format single-line block properly when adding a field initializer in it.

Annotate VisualStudioWorkspace, VisualStudioProject and friends

This is now annotated as non-null, so the check is pointless.

These are all functions are supposed to work equally well with
regular documents, additional documents, and analyzer config documents.
However, they were all calling GetDocument that would only work with
the first kind.

The annotation is for the most part straightforwad. This removes a hack
where rather than passing some things through the VisualStudioProject
constructor, we just assigned some properties after creation. This
is now cleaned up since it made annotation problematic.

Update Microsoft.CodeAnalysis.Workspaces to target netcoreapp3.1

Disable unimported types completion in liveshare until we have suppor…

Share file header analyzer with the code style layer

Add a comment to the newly added asserts related to editorconfig options

Port RemoveUnnecessaryImports analyzer/fixer/tests to shared layer

Use proper asynchronous methods in PreviewFactoryService

Port C# UseImplicitType and UseExplicitType analyzers to shared layer

Limit cascading when finding the set of members to update when switching member to be explicit.

* Update dependencies from https://github.com/dotnet/arcade build 20200304.1

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.20154.1

* Update dependencies from https://github.com/dotnet/arcade build 20200305.4

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.20155.4
Co-authored-by: Ndotnet-maestro[bot] <dotnet-maestro[bot]@users.noreply.github.com>

Add finer-grained cancellation token checks during some find operations

Update src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Services/SyntaxFacts/AbstractSyntaxFacts.cs
Co-Authored-By: NDavid Kean <davkean@microsoft.com>