[clang] Extend -Wnonportable-include-path with a warning about trailing whitespace or dots (PR #96960)

[Aaron Ballman via cfe-commits]

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@@ -361,7 +361,11 @@ class NonportablePath  : Warning<
   "non-portable path to file '%0'; specified path differs in case from file"
   " name on disk">;
 def pp_nonportable_path : NonportablePath,
-  InGroup<DiagGroup<"nonportable-include-path">>;
+  InGroup<NonportablePath>;
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AaronBallman wrote:

I would be nice to give the diagnostic group a different identifier (the name we expose to users is fine!) so that we don't have this weird naming conflict between the diagnostic group and the `class NonportablePath` definition a few lines up from here.

https://github.com/llvm/llvm-project/pull/96960