[clang] Fix false match on nullPointerConstant for array indices (PR #201893)

[Kay Hicketts via cfe-commits]

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@@ -980,6 +980,8 @@ AST Matchers
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 - Add ``functionTypeLoc`` matcher for matching ``FunctionTypeLoc``.
 - Add missing support for ``TraversalKind`` in some ``addMatcher()`` overloads.
+- Fixed ``nullPointerConstant`` matcher falsely matching integer literal ``0``
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KHicketts wrote:

that's true.  I could also add a unit test to make that explicit.

https://github.com/llvm/llvm-project/pull/201893