This contradicts CPython, in `Lib/numbers.py`, because `Real` does not
actually inherit from `SupportsFloat`. But it suppresses errors from
mypy when passing sub-classes like `fractions.Fraction` to `float()`.
* Partially refine numbers.pyi
This commit refines numbers.pyi. More specifically, it...
- Adds in explicit type annotations where it's obvious how to do
so (leaving more non-obvious type signatures alone).
- Adds in missing '@abstractmethod' decorators
- Combines together the Python 2 and Python 3 versions of numbers.pyi.
* Merges Python 2 and Python 3 numbers.pyi
This commit removes the old `stdlib/2.7/numbers.pyi` file and moves the
previously-committed `stdlib/3/numbers.pyi` to the shared `2and3`
directory.
* Modify comment at top of numbers.pyi
Since the stubs are no longer identical to what stubgen creates, the
comment should also probably be changed.
