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/LibDriver/LibDriver.cpp b/llvm/lib/LibDriver/LibDriver.cpp
index 4492958..fb8e0a8 100644
--- a/llvm/lib/LibDriver/LibDriver.cpp
+++ b/llvm/lib/LibDriver/LibDriver.cpp
@@ -53,7 +53,7 @@
   LibOptTable() : OptTable(infoTable, llvm::array_lengthof(infoTable), true) {}
 };
 
-}
+} // namespace
 
 static std::string getOutputPath(llvm::opt::InputArgList *Args) {
   if (auto *Arg = Args->getLastArg(OPT_out))