R1:f712ae718ccc

Added `-` to the whitelist for CSS rules

Summary: Fixes T11567. This way people can use things like `sans-serif` and `-webkit-small-control` for their "monospaced" font

Test Plan:
I added the hyphen to the regex then was able to set my Monospaced Font to be anything with a hyphen in it.

I also tried to break it pretty extensively, but couldn't find anything that would let me write malicious CSS or JS.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers…