Co-Authored-By: NSam Harwell <sam@tunnelvisionlabs.com>

#39955 re-added the option back to Workspaces instead of Features, its original location

Co-Authored-By: NSam Harwell <sam@tunnelvisionlabs.com>

Recent PR #39699 introduced a breaking API and functionality change for TypeScript and F# as they are using our internal option ClosedFileDiagnostics for controlling their full solution analysis experience. This PR restores the ClosedFileDiagnostics option and functionality for non C#/VB languages. Additionally, the newly added option SolutionCrawlerOptions.BackgroundAnalysisScope has been made a per-language option so that all languages can have different UI/setting for this option.

Revert the hard coded name check for SBD incremental analyzer as unit test team has moved to IUnitTestingIncrementalAnalyzer

Co-Authored-By: NJason Malinowski <jason@jason-m.com>

Change how we get both assembly symbol and metadata reference from a project's references, which improves perf by avoiding mapping assemblies to project.

Before:
compilation -> referenced assembly symbols -> metadata references |-> projects
                                                                                                              |-> PE references
now:
compilation |-> referenced projects -> assembly symbols -> corresponding metadata references
                    |-> referenced PE references -> assembly symbols

* Implement lambda discard parameters

* Remove duplicate tests

* Factor logic to recognize underscore tokens

* Align symbol display with other discards

* Distinguish discards in QuickInfo

* Add IsDiscard property instead of IDiscardSymbol

* Adjust IDE logic to use IsDiscard

* Avoid large tuple return

* Add test for ref/out discard parameters

* Address PR feedback and test plan ideas

* Allow in expression trees

* Support general discard parameters

* Add IDE tests

* Emit with unspeakable name

* Remove unused error code

* Only support lambdas

* Fix tests

* Address some PR feedback

* Address remaining feedback

* Address more feedback

* Fix conflict

* Update PublicAPI.Unshipped.txt

* Update PublicAPI.Unshipped.txt

* Add ChangeSignature tests

* Add SymbolCompletion tests

* Add InlineRename test

* Typo