Support for complex completions with InlineDescription

[kindermannhubert]

Version

last

What happened?

After upgrading Microsoft.CodeAnalysis.CSharp.Features 4.4.0 -> 4.5.0, CompletionService returns items with IsComplexTextEdit==true && InlineDescription.Length > 0. Typically these are items from not-inluded namespaces.

In VS it looks like this:

Now we are filtering these items out (in AutoCompleteService.Complete) but we should support their insertion.

For clarification: we are filtering them out now because they are colliding with existing items (same DisplayName).