Breaks the internal GTD infrastructure into seperate symbols for
determining the navigable symbol at the caret position and performing
the navigation.

If you create an elision buffer, there's no way to disconnect the
elision buffer from the underlying buffer once you're done with it,
causing the elision buffer to leak. It's possible to disconnect
projection buffers, so we use them to work around this limitation.

When we create a projection buffer, that buffer is strongly held by
the underlying buffer, which means we have a memory leak unless we
disconnect it by unmapping all spans. This also causes problems because
bugs in the editor around projections can then cause crashes when we
didn't actually need the buffers anymore.

Revert "Merge pull request #20558 from Pilchie/Fix19968-DuplicateSourceAndAdditionalFiles-DistinctIds"

This reverts commit 6f5b2d47, reversing
changes made to 66362df5.

If the user closes a textview while completion is filtering, it's possible for the filtering task to ask for a Document before it gets cancelled, resulting in a crash. To prevent this, restrict Controller.GetDocument() to the foreground thread.

This is a breaking API change.  Need to decide if we want to take it or
not.

made diagnostic engine to verify span given to diagnostic from analyzers. and added explicit check in tagger for out of range

Fixes
https://devdiv.visualstudio.com/DevDiv/_workitems?id=391624&_a=edit

- Inline Rename fields now consist of a themeable/customizable
background, foreground, and border. The border is used in High Contrast.
- Resolved and Unresolved conflict borders can now be themed &
customized.
- Resolved and Unresolved conflict borders now have different dash
styles so they are distinct from each other and regular Inline Rename
fields. The Dashboard shows a key indicating which type of conflict
corresponds to which border dash style.

We believe that the primary cause of this exception (some issues around
projection buffers) was worked around in d8f8dad3 but we're still
seeing issues so that's not the case. I'm also further not convinced
that change helped at all, because in many case we already fork
buffers to work around the same issue.

We simply have to produce IErrorTag with with "hinted squiggle" type and the editor will make tooltips and the adornment "just work"

Fix EditAndContinueDiagnosticUpdateSource.ReportDiagnostics to return correct set of documents (#19786)

Also updates other references based on Preview 1 and moves from
Microsoft.Composition to System.Composition

To address accessibility issues, the editor has added its own handler for the INvokeQuickInfo command. We therefore need to remove Roslyn's handling of the same command.

Because completion asynchronously computes descriptions, the default
text is "...". In order to present the description when available, we
have to set the AutomationProperties.Name on our tooltip UIElement.

Sometimes completion filtering crashes in MatchesFilterText. From
inspecting the code, it appears that the only possible cause is that a
null completionHelper is passed in. The method that retrieves a
CompletionHelper sometimes returns null. This change will cause a crash
instead, allowing us to investigate why the Document was null, or try to
further determine why MatchesFilterText might crash.