Proposing a PR to fix a few small typos

[timgates42]

Issue Type

[x] Bug (Typo)

Steps to Replicate and Expected Behaviour

• Examine flask_peewee/admin.py, flask_peewee/rest.py and observe certian, however expect to see certain.
• Examine docs/auth.rst and observe reserverd, however expect to see reserved.
• Examine docs/gevent.rst and observe preferrably, however expect to see preferably.
• Examine flask_peewee/tests/admin.py and observe nonexistant, however expect to see nonexistent.

Notes

Semi-automated issue generated by https://github.com/timgates42/meticulous/blob/master/docs/NOTE.md

To avoid wasting CI processing resources a branch with the fix has been prepared but a pull request has not yet been created. A pull request fixing the issue can be prepared from the link below, feel free to create it or request @timgates42 create the PR.

https://github.com/timgates42/flask-peewee/pull/new/bugfix_typos

Thanks.