[trivial] Add end of namespace comments

src/compat/glibcxx_sanity.cpp

@@ -38,7 +38,7 @@ bool sanity_test_list(unsigned int size)
     return true;
 }
 
-} // anon namespace
+} // namespace
 
 // trigger: string::at(x) on an empty string to trigger __throw_out_of_range_fmt.
 // test: force std::string to throw an out_of_range exception. Verify that