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.

Always insert the insertion text, even when we can't resolve symbols.

Fixes #12254

Fix command line parsing of quoted values

Add extra logging to invocation of ibcmerge...

Add partial-type-name suggestions to C# and some fixes for VB

Merge dev15-preview-4 into master

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Fix a bad merge

removed stale references to Concord.csproj

This is causing signing to fail without any messages.  Not on the critical path.

Move Roslyn.VisualStudio.Setup.Interactive.dll to be regular signed

Ensure IBC is running for our official builds.

There will be a corresponding update to the Build Definitions to provide the $(IbcMergePath) value.

Merge dev15-preview-4 into master

Previously, a tuple in a declaration context always required a
TupleElementNamesAttribute to record the names. Now, when the tuple has
no names the compiler will elide the attribute. On loading from
metadata it is assumed that tuples without an attribute have no names.

Fixes #12454

Add binding redirect for System.Collections.Immutable

# Conflicts:
#	src/Tools/SignRoslyn/BinaryData.json

Merge microupdate into dev15-preview-4

Merge microupdate into master