Add optional `if break:` suite to `for/while`

[Nodd (Joseph Martinot-Lagarde)]

@Stefan2

That’s nothing special. That’s the same for any code that’s not reached because you returned before you got to it.

Well, it seems to be a problem in the case of try-finally : PEP 765: Disallow return/break/continue that exit a finally block

I’m not saying that it is a problem in for-else, I’m just making a parallel.