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/Sema/SemaCodeComplete.cpp

@@ -342,7 +342,7 @@ namespace {
     bool IsImpossibleToSatisfy(const NamedDecl *ND) const;
     //@}    
   };  
-}
+} // namespace
 
 class ResultBuilder::ShadowMapEntry::iterator {
   llvm::PointerUnion<const NamedDecl *, const DeclIndexPair *> DeclOrIterator;
@@ -1264,7 +1264,7 @@ namespace {
       Results.AddResult(Result, CurContext, Hiding, InBaseClass);
     }
   };
-}
+} // namespace
 
 /// \brief Add type specifiers for the current language as keyword results.
 static void AddTypeSpecifierResults(const LangOptions &LangOpts,