support for comments

[UnquietCode]

Support comments in the generated markdown. See the example issues.py in the root of the repository for a starting point. The comments can be rendered in a new section after the end of the issue description.

Maybe something like....

@UnquietCode wrote on January 4th, 2021:

Comments are cool.

And

multiline comments t00

• [x] titles are good
• [x] body is good
• [x] spacing is good

[iceplant]

Block quotes aren't implemented so I'm just leaving the comment body as a paragraph. I can add that if it's important.

Edit: "quote" is a block quote.