Should enforce the framework style import

[woshimaliang]

Today, both import styles work when import framework headers:

#import "SomeFrameworkHeader.h"

#import <SomeFramework/SomeFrameworkHeader.h>

And ideally only the framework style import should be allowed.

[rahul-malik]

I agree this would be nice to enforce but flagging as an area of improvement for now since it isn't affecting builds