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
diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index e609fcf..b6559b2 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -4924,7 +4924,7 @@
       Diags.popMappings(SavedLoc);
   }
 };
-}
+} // namespace
 
 OMPClause *Sema::ActOnOpenMPFirstprivateClause(ArrayRef<Expr *> VarList,
                                                SourceLocation StartLoc,