[clang-tools-extra] [clangd] Update XRefs to support overriden ObjC methods (PR #127109)

[kadir çetinkaya via cfe-commits]

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@@ -430,6 +430,18 @@ locateASTReferent(SourceLocation CurLoc, const syntax::Token *TouchedIdentifier,
         continue;
       }
     }
+    // Special case: an Objective-C method can override a parent class or
+    // protocol.
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kadircet wrote:

> I was thinking for that users can use go to implementation to find them.

i think using go-to-definition for such interactions is a more common workflow (also go-to-impl is not necessarily implemented by all editors). so I think there's merit in making sure that also works (though I won't block this patch on it, as it's not a regression. but I think it warrants at least a `FIXME`)

https://github.com/llvm/llvm-project/pull/127109