Address many suggestions in the 'Features' projects.

Fix formatting issues being flagged by the analyzer

Remove unused method from sighelp

Merge release/dev16.3-preview1 to master

- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19326.44

When a .ruleset file includes a non-existing ruleset reference we receive null from ResolveIncludePath and throw a FileNotFoundException, which is the immediately caught in LoadRuleSet.

We can avoid the first-chance exception and the associated allocations if we just return null. A missing ruleset is not an exceptional situation so no need to use exceptions for control flow here if we can avoid it.

Skip BasicEditAndContinue tests

 Skip BasicEditAndContinue tests

Merge 16.3-preview1 to master