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

The patch is generated using this command:

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

To reduce churn, not touching namespaces spanning less than 10 lines.

llvm-svn: 240270

clang/lib/Serialization/ModuleManager.cpp

@@ -534,7 +534,7 @@ namespace llvm {
       return M->ModuleName;
     }
   };
-}
+} // namespace llvm
 
 void ModuleManager::viewGraph() {
   llvm::ViewGraph(*this, "Modules");