[docs] [issue12704] Language Reference: Clarify behaviour of yield when generator is not resumed

Changes by Nikolaus Rath <Nikolaus@rath.org>: ---------- title: Language References does not specify exception raised by final yield() -> Language Reference: Clarify behaviour of yield when generator is not resumed _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue12704> _______________________________________