Restored tag parsing when checking for reserved tags

- had been accidentally deleted in an earlier refactoring.
A bit worrying that this didn't get spotted sooner!

include/internal/catch_test_case_info.hpp

@@ -30,7 +30,7 @@ namespace Catch {
             return TestCaseInfo::None;
     }
     inline bool isReservedTag( std::string const& tag ) {
-        return TestCaseInfo::None && tag.size() > 0 && !isalnum( tag[0] );
+        return parseSpecialTag( tag ) == TestCaseInfo::None && tag.size() > 0 && !isalnum( tag[0] );
     }
     inline void enforceNotReservedTag( std::string const& tag, SourceLineInfo const& _lineInfo ) {
         if( isReservedTag( tag ) ) {