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/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index d690a79..53950ae 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3046,7 +3046,7 @@
   void getAnalysisUsage(AnalysisUsage &AU) const override;
   bool runOnFunction(Function &F) override;
 };
-}
+} // namespace
 
 void InstructionCombiningPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesCFG();