Add font: Reddit Mono (SIL OFL)

[AkshayChn]

Information we need about new fonts:

• What's it called?
  Reddit Mono
• Where did you find it? Preferably the website of the creator of the font.
  GitHub: https://github.com/reddit/redditsans
  Website: https://redditsans.s-ings.com/
• Where can we download it?
  Here: https://redditsans.s-ings.com/Reddit%20Sans%201.012.zip
• What's the license?
  SIL OFL v1.1

[braver]

Hey, that's cool. Thanks!

[AkshayChn]

Please see if the year should be corrected to 2023. It is showing 2020 on programmingfonts.org

[braver]

I had it at 2023 at first, but the first versions of the GitHub repo are actually from 2020.