[3.14] annotationlib docs: note that ForwardRef.evaluate eventually defaults to empty globals (GH-134661) (#134662)

annotationlib docs: note that ForwardRef.evaluate eventually defaults to empty globals (GH-134661)
(cherry picked from commit b51b08a0a5fedde4f74e4cc338b8b5ad9656ad50)

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>