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/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f750638..2e62ea6 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -89,7 +89,7 @@
   bool AllowClassTemplates;
 };
 
-}
+} // namespace
 
 /// \brief Determine whether the token kind starts a simple-type-specifier.
 bool Sema::isSimpleTypeSpecifier(tok::TokenKind Kind) const {
@@ -2501,7 +2501,7 @@
   QualType PromotedType;
 };
 
-}
+} // namespace
 
 /// getSpecialMember - get the special member enum for a method.
 Sema::CXXSpecialMember Sema::getSpecialMember(const CXXMethodDecl *MD) {
@@ -6606,7 +6606,7 @@
   CXXRecordDecl *ExpectedParent;
 };
 
-}
+} // namespace
 
 /// \brief Generate diagnostics for an invalid function redeclaration.
 ///
@@ -8758,7 +8758,7 @@
 
     SelfReferenceChecker(S, OrigDecl).CheckExpr(E);
   }
-}
+} // namespace
 
 /// AddInitializerToDecl - Adds the initializer Init to the
 /// declaration dcl. If DirectInit is true, this is C++ direct