A few small fixes

Hey there, I just joined tilde.red and saw some small things I wanted to fix, and since there's a Github repo I decided to submit a pull request (also, I've never submitted a pull request before so I wanted to try :3). The things I've changed are:
- Some small English errors (spelling, grammar, wording, etc.)
- I turned the rules in to an ordered list, seems a bit easier to read to me
- I indented most of the HTML, it's still a bit weird in some of the head sections, but all the body sections are now a bit easier to read

So I hope you're willing to pull these changes, but if not, no biggie. ;)