Remove trailing whitespace in DiagnosticSemaKinds.td. NFC (#155482)

Author: rampitec

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -12618,7 +12618,7 @@ def warn_zero_as_null_pointer_constant : Warning<
   InGroup<DiagGroup<"zero-as-null-pointer-constant">>, DefaultIgnore;
 
 def warn_not_eliding_copy_on_return : Warning<
-  "not eliding copy on return">, 
+  "not eliding copy on return">,
   InGroup<DiagGroup<"nrvo">>, DefaultIgnore;
 
 def err_nullability_cs_multilevel : Error<