F1 shows man page for current query

[serpent7776]

Description

Make F1 key launch man page for current query. E.g. I have CREATE TABLE foo as my query and I press F1. The man page CREATE_TABLE is launched. This requires man pages to be installed locally, I'm not sure they're always installed. I have it on my manjaro, but I don't see man pages on ubuntu, only the html docs.

This is currently just a scratch implementation, let me know if you're interested in having such functionality.

Also, I'm not a python dev, any suggestions welcomed.

Checklist

• [ ] I've added this contribution to the changelog.rst.
• [ ] I've added my name to the AUTHORS file (or it's already there).

• [ ] I installed pre-commit hooks (pip install pre-commit && pre-commit install), and ran black on my code.
• [x] Please squash merge this pull request (uncheck if you'd like us to merge as multiple commits)