Add Roslyn Dev16.1 Preview 3 entries to azure-pipelines .yml files

* Add import placement codestyle option

* Add TextEditor CodeStyle options for Using Placement

* Add misplaced using directives analyzer and code fix

* Use consistent pluralization

* Removed Preserve AddImportPlacement option

* Removed Preserve from CSharp Style Options

* Removed Preserve from editorconfig tests

* Coverted to Roslyn style analyzer and fixer tests.

* Simplified MisplacedUsings CodeFix based on feedback.

* Simplified MisplacedUsings CodeFix based on feedback.

* Add warning annotation to moved using directives

* Move misplaced usings out of multiple namespaces

* Deduplicate usings when moving them

* Simplified move usings warning text

* Add expected warning markers to misplaced using tests

* Fix editor config generator tests

* Consolidated diagnostics and tests

* Add tests where directives are in both contexts

Add telemetry for import completion

Re-enable set -e 

This reverts commit 42fe72da.

Fix sorting of import completion items

Binary log for Unix bootstrap

Generate a binary log file for the bootstrap phase on Unix platforms.

Target Typed Completion Prototype

* Fix for 34983

* Cleanup, fix For statements

* Add more tests

* Respond to feedback

* Fix spelling

Correctly report null reference possibility when GetEnumerator returns a potentially nullable Enumerator type.

Avoid caching VS completion items for non-import items

Revert "Remove the dependence between the order in NullableAnnotation and metadata attribute values (#34909)"

This reverts commit e922628a.

Cleanup missed prototype comments.

Merge features/editorconfig-in-compiler back into master

🔼 Avoid FailFast for VS service missing during shutdown