Fixed/added namespace ending comments using clang-tidy. NFC

The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!

llvm-svn: 240137
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index ab30aa1..68986ac0 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -77,7 +77,7 @@
     Instruction *splitOverflowIntrinsic(Instruction *IVUser,
                                         const DominatorTree *DT);
   };
-}
+} // namespace
 
 /// Fold an IV operand into its use.  This removes increments of an
 /// aligned IV when used by a instruction that ignores the low bits.