Renamed _PyInterpreterFrame as _Py_frame to emphasise its close association with PyFrameObject (they're conceptually the same thing, but split into a Python object struct and a C data struct as a performance optimisation).

The f_ prefix has been removed from all _Py_frame fields that previously used it, so the presence or absence of the prefix provides a way to infer the exact type of a frame pointer when reading an isolated snippet in a code diff.