Revert making ``from __future__ import annotations`` the default. This follows
the Steering Council decision to postpone PEP 563 changes to at least Python
3.11. See the original email for more information regarding the decision:
https://mail.python.org/archives/list/python-dev@python.org/thread/CLVXXPQ2T2LQ5MP2Y53VVQFCXYWQJHKZ/.
Patch by Pablo Galindo.
