Democratizing code fixes - part two

[psfinaki]

This PR:

• adds an F#-friendly represantation of code fixes - FSharpCodeFix
• extends the code fix framework so that it now returns an option: this is because code fixes are bound to diagnostics but sometimes they shouldn't trigger respective changes (e.g. FS0039)
• adds negative unit tests to demonstrate this
• adds a helper to CodeFixHelpers to reduce the repeating boilerplate
• refactors and adds tests for three more code fixes
• fixesFSharpWrapExpressionInParentheses code fix throws exception #15397 - it's the same story as Convert To Anonymous Record code fix is broken #15372

As of now, the code fix boilerplate is only the following:

override_.FixableDiagnosticIds= ImmutableArray.Create(...)// diag numbers hereoverridethis.RegisterCodeFixesAsync context = context.RegisterFsharpFix(this)interface IFSharpCodeFixProvider withmember_.GetCodeFixIsAppliesAsync document span =// implementation

[psfinaki]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).