Fixes https://dev.azure.com/devdiv/DevDiv/_workitems/edit/1135706

* Rename

* Change the name to Pascal style

* Rename the enum and change the wrong string

This is a performance improvement to avoid creating so many file
watchers in Visual Studio. The Visual Studio file watching service
consolidates file watchers to a single directory, but still has to
manage the list of all of the file names we are trying to watch so it
can appropriately filter, and the work to create all of that tracking
is entirely unnecessary since in practice we're just going to watch
all the files of a particular extension under a directory.

This is an optimization in that the FileChangeWatcher and does not
impact correctness. When the FileChangeWatcher is asked to watch a file,
it checks to see if the the file is under the directory and matches any
extension filter; if not, it'll still create a regular file watch under
the covers. This is opaque to the users, since they're getting file
watches and will see change notifications either way. It's just a
performance hint to avoid unnecessary work.

This required updating our mock implementation of the Visual Studio
file change service to support requests for directory watching and for
handling the filtering of them.

Fixes https://github.com/dotnet/roslyn/issues/13679
Fixes https://github.com/dotnet/roslyn/issues/42095

I am just a simple developer trying to send these cancellation tokens downstream where they belong

* Revert "Revert "Refactoring of Active Statement tracking for OOP""

* Only apply active statement tracking for C# and VB buffers

Fixes #44603

* RemoveHostClientProvider

* Do not start ServiceHub in command line mode

* Unused usings

* CreateConnection can no longer return null

* Connection refactoring

* Feedback

* Feedback

* Workaround for CodeLens issue

* Address NuGet PackageInstall failure

* Remove NuGet workaroud fixed in 15.9

* Fix potential hang

Fixes #43255

* Add additional testing.
* Implement symbol equivalence for function pointer types.
* Simplify the change signature dialog type resolution.

This reverts commit 680a020f.

* Offer `delegate` keyword when function pointer types are permissible.
* Completion inside function pointer type argument lists (including valid ref modifiers)
* SymbolKey support.
* Basic formatting support.
* Support in add/remove parameter.

* RemoveHostClientProvider

* Dispose cancellation source

* Do not start ServiceHub in command line mode

* Unused usings

* Fix

* Do not remote operations on non-VS Workspace

* Better tests

* Move IDebuggeeModuleMetadataProvider to EditSession

* Move pending update to EditSession

* ASTS refactoring

* Move AS enumeration to EditSession

* Separate ASTS from EditSession

* Pass Solution explicitly

* Separate ASTS (in-proc) from span tracker (OOP)

* Use pull model for AS updating

* Do not use view tagger provider

* Fix tests

Related to #41704.

variables of the desired type

* Remove remote host restarting logic

* RemoteServiceName

* Remove dependency on Workspace

* Refactoring

* Fixes

This replaces our existing "GetDocumentFromURI" helper with one that
instead takes the full TextDocumentIdentifier, and uses the context
information to figure out which document to use in the case of
multi-targeting or linked documents.