distinguishing bikeshed errors better in drafts.{csswg,fxtf,css-houdini}.org status

https://drafts.csswg.org/ https://drafts.fxtf.org/ and
https://drafts.css-houdini.org/ have a bikeshed icon along the right
column.  It currently seems to have the state:

 * green: no errors/warnings
 * #08f (light blue): bikeshed warning
 * #aa0 (light olive?): bikeshed link error
 * #d00: red:
   - bikeshed "fatal error" that was overridden by -f
   - bikeshed threw an exception and didn't generate a spec

Perhaps there should be a distinction between these last two --
failing to generate a spec is substantially worse than the
overridden bikeshed "fatal errors".  (e.g., css-typed-om and
css-module-bikeshed are in the fail-to-generate state right now for
the same bikeshed bug, whereas the other red specs are mostly broken
biblio stuff, and occasionally other broken linking stuff, or
indices being broken by lack of a TR entry).

Maybe a bikeshed exception (or other failure to generate?) should be
red-on-black or something really serious looking?

-David

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                          https://www.mozilla.org/   𝄂
             Before I built a wall I'd ask to know
             What I was walling in or walling out,
             And to whom I was like to give offense.
               - Robert Frost, Mending Wall (1914)