Respect filter flags when searching for symbols.

Fixes #12169

References were partially updated, causing downgrading for missed projects.

Merge dev15-preview-4 into master

Correct the version number and move them to the Targets

Additional typeswitch tests.

Correct typo in Semantic/ValueTupleTests. #12010

Check VSIX certificates

Correct the version number and move version to the Targets

Adds checks to the batch signing tool:

1. VSIX should be signed with VSIX certificates.
2. Non-VSIX should not be sigend with VSIX certificates.

A mistake of this nature previously broke signed builds.

A number of types / files ended up with names I wasn't happy with.  Updated them all.

Add dependencies between Swixproj

The Swixproj projects encapsulating each Vsix should mention the
dependencies betweeen them similar to the dependencies stated in the
contained Vsixes.

Add dependencies between Swixproj

Merge dev15-preview-4 into master

The Swixproj projects encapsulating each Vsix should mention the
dependencies betweeen them similar to the dependencies stated in the
contained Vsixes.

Refactor completion insertion

Remove unnecessary override.

Object creation providers don't need to compute insertion text.

Fixes #11812 

Remove unneeded parameters.  Simplify data passed in completion.

Avoid resolving symbols at insertion time.