Also fixes comments in a lot more places than a few commits ago.
Syntax like the following is proper, and the comment highlighting fixes
from last commit make the incorrect highlighting here really stand out:
```factor
USE: ! only this line highlights
kernel
```
This lets Factor's overly long line highlighting avoid bleeding over
into documentation source buffers, or buffers of other non-Factor file
types entirely. Also, by taking `:2match` instead of `:match`,
clobbering of most user matches (or vice versa) can be avoided.
Unfortunately, the highlighting effects all windows in a multi-buffer
split setup, but since we can't reasonably make this a `:syntax match`
group, it'll have to do. (And this behavior isn't new.)
Dusk
Alexander Iljin