Hard code (higher) max-width for comments.

#2 turned out to have negative side effects in the context of code lines that are wider than the screen width. This puts a reasonable hard limit on it that works well down to a screen resolution of 1280x800 (which, incidentally, is what I think I'll start using as the functional baseline).
Merge pull request #3 from TravisCarden/patch-1

Hard code (higher) max-width for comments.