Keep semicolon after NS_ENUM & NS_OPTIONS declaration (OC).

In Objective-C, ```mod_remove_extra_semicolon``` should not treat the semicolon after an ```NS_ENUM``` or ```NS_OPTIONS``` declaration as superfluous.

I've added a test case that reproduces the problem, and a patch that appears to fix it. (C++ is not my strength, so it may need improving.)