[clang] Use existing AvailabilityKind enum for code completion availability (PR #160296)

[Vlad Serebrennikov via cfe-commits]

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@@ -3197,12 +3188,47 @@ def __repr__(self) -> str:
         )
 
 
-availabilityKinds = {
-    0: CompletionChunk.Kind("Available"),
-    1: CompletionChunk.Kind("Deprecated"),
-    2: CompletionChunk.Kind("NotAvailable"),
-    3: CompletionChunk.Kind("NotAccessible"),
-}
+# AvailabilityKindCompat is an exact copy of AvailabilityKind, except for __str__
+# This is a temporary measure to keep the string representation the same
+# until we unify the return of CompletionString.availability to be AvailabilityKind
+# Note that deriving from AvailabilityKind directly is not possible
+class AvailabilityKindCompat(BaseEnumeration):
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Endilll wrote:

Can we hid this inside `CompletionChunk`, so that it doesn't pop up in autocompletion as easily as `AvailabilityKind` itself?

https://github.com/llvm/llvm-project/pull/160296