Add stub files for PRAW

[PythonCoderAS]

As per #1144 I will be adding in a folder of stub files that match the expected types in every function, class and method. I tried my best to figure out the types from the corresponding docstrings, but some of them might be erroneous. Please send a PR with any corrected mistakes.

The blank templates were generated with mypy's stubgen --doc-dir ./docs/ -p praw -o ./stubs/ which was run in the base directory of the repo. This requires that the development praw be installed, as the -p option will import praw. mypy can be obtained through pip install mypy.

[PythonCoderAS]

There are stub files for every file, but not all of them are filled in.

[PythonCoderAS]

Official Statusboard:

praw

• config.py
• objector.py
• init.py
• exceptions.py
• reddit.py
• endpoints.py
• const.py

praw/util

• cache.py
• init.py
• snake.py

praw/models

• redditors.py
• auth.py
• subreddits.py
• user.py
• util.py
• preferences.py
• init.py
• mod_action.py
• inbox.py
• comment_forest.py
• front.py
• trophy.py
• modaction.py
• stylesheet.py
• helpers.py
• base.py

praw/models/list

• init.py
• redditor.py
• trophy.py
• base.py

praw/models/reddit

• comment.py
• emoji.py
• multi.py
• submission.py
• init.py
• message.py
• redditor.py
• wikipage.py
• widgets.py
• subreddit.py
• more.py
• collections.py
• modmail.py
• live.py
• removal_reasons.py
• base.py

praw/models/reddit/mixins

• reportable.py
• editable.py
• inboxtoggleable.py
• replyable.py
• gildable.py
• init.py
• fullname.py
• votable.py
• inboxable.py
• messageable.py
• savable.py

praw/models/listing

• domain.py
• init.py
• listing.py
• generator.py

praw/models/listing/mixins

• rising.py
• submission.py
• init.py
• redditor.py
• gilded.py
• subreddit.py
• base.py