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!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240137 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/OptimizePHIs.cpp

@@ -55,7 +55,7 @@ namespace {
     bool IsDeadPHICycle(MachineInstr *MI, InstrSet &PHIsInCycle);
     bool OptimizeBB(MachineBasicBlock &MBB);
   };
-}
+} // namespace
 
 char OptimizePHIs::ID = 0;
 char &llvm::OptimizePHIsID = OptimizePHIs::ID;