Defer to a service to actually find references.  That way we can call out to a remote process to do this work at the VS layer.

Allow esent to be used in the remote process.

* In a syntactic position where an lvalue is expected, we reserve `var (...)`
for possible future extension (e.g. a deconstruction), no matter what `...` is.
This specifically applies to
  - The left-hand-side of an assignment. The only syntactically valid form is as a deconstruction declaration statement; other forms are some kind of error. `var(1) = 2;`
  - Similarly for compound assignments, including ++ and --.
  - In any expression, following `out` or `ref`. These should not bind (successfully) as an invocation.
    - In an argument position, like `M(out var (1))`
    - In a "ref expression", for example `ref int x = ref var(1);` or `return ref var(1);`.

remove exteranl dependencies we can get from devenv.exe.config

add new RemoteHostClient which will run services in proc

this is to make develop - debug cycle easiler when adding new features to service hub.

to enable this, turn on Roslyn/FeatureManager/Features/RemoteHost and RemoteHostInProc

once enabled, InProcRemoteHostClient will be used instead of ServiceHubRemoteHostClient

except concrete type of RemoteHostClient, all other parts, exactly same code will be used.

InProcRemoteHostClient can be used in unit test to test client and server side as they are.

 Suggestion tag improvements.

Fixes #13496

Fix for nested param/typeparam suggestions

1. Increase opacity
2. Support user configuration of the suggestion tag color.
3. Refresh the color when the user changes fonts and colors.

Handle names in long tuples in EE

Merge future to master

Only declare Hidden Descriptors for SimplifyTypeName/QualifyMemberAccess

* Enable declaration patterns in the EE

Fixes #13159 

Properly handle expression variable declared within VariableDeclaratorSyntax.ArgumentList in field declarations.

Re-add property that internal CodeLens implementation depends on