Doc updates

[ryansurf]

A simple PR, addressing some of the issues @K-dash mentioned in #38

What I've done:

• Removed start_venv.sh, which is no longer needed after the introduction of Poetry
• Added a command to cheat_sheet.md and fixed a typo

I've also created a pre-commit hook to update structure.md, but I'm trying to figure out how/if I should push that to the repo.

Since this PR just fixes a typo and deletes an unnecessary file, I'm going to merge it. No functionality will be changed

[github-actions[bot]]

Coverage Report

File	Stmts	Miss	Cover	Missing
src
__init__.py	0	0	100%
api.py	86	6	93%	30, 48, 70–71, 103–104
art.py	9	3	67%	24–25, 37
cli.py	23	4	83%	34, 50–51, 55
gpt.py	10	6	40%	16–21, 32–45
helper.py	143	52	64%	50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 81, 92–96, 129–137, 149, 162–163, 181–183, 193, 195–196, 218–219, 256–266, 273–281
send_email.py	24	24	0%	5–48
server.py	41	41	0%	5–82
settings.py	22	0	100%
TOTAL	358	136	62%

Tests	Skipped	Failures	Errors	Time
9	0 :zzz:	0 :x:	0 :fire:	12.667s :stopwatch: