docs: PR title generator & update contributing guideline

[scarf005]

Purpose of change

make opening PR (and following requirements) easier for beginners.

Describe the solution

• auto-update semantic.yml (and allowed mod list)
• made checklist more prominent
• added pr title generator in docs page

Describe alternatives you've considered

using UI framework like preact over raw dom manipulation, but the component was simple enough.

Testing

Additional context

2024-06-16_20-28-26.mp4

Checklist

• I wrote the PR title in conventional commit format, see above
• I ran the code formatter
• I linked any relevant issues using github keyword syntax

[chaosvolt]

* made checklist more prominent

Shit, I didn't see this and also didn't realize it meant bringing back the checklist spam that was removed in #3677 specifically because it's a nuisance for 90% of PRs, or I wouldn't have approved this.

[scarf005]

it does say to remove unrelated sections, tho

[chaosvolt]

Yes but that's a pointless annoyance to clutter every single PR with when 90% of it just gets removed.

[chaosvolt]

Eh, for now we can leave it be, see if it helps anyone and just comment it out if others complain I guess.