Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)

Apparently, the style needs to be agreed upon first.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240390 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/StringSet.h

@@ -29,6 +29,6 @@ namespace llvm {
       return base::insert(std::make_pair(Key, '\0'));
     }
   };
-} // namespace llvm
+}
 
 #endif // LLVM_ADT_STRINGSET_H