[lint] Fix import order

Reorder imports to be consistenly grouped by standard library, third
party library, and local modules in that order thoughout the library.

discord/abc.py

@@ -27,7 +27,6 @@ DEALINGS IN THE SOFTWARE.
 import abc
 import copy
 import asyncio
-
 from collections import namedtuple
 
 from .iterators import HistoryIterator