Add tailwinds-based abbreviations

[stephenh]

We originally chose Tachyons abbreviations, but there's no reason truss couldn't provide either Tachyons-ish or Tailwinds-ish abbreviations.

(It's unlikely that, within Homebound, we'd switch to Tailwinds-style abbreviations, but net-new users of Truss might prefer the Tailwinds abbreviations given it's been more widely adopted than Tachyons.)