make `tsf` work on `\dfrac`

[ces42]

It would be useful if tsf could convert \dfracs into inline fractions (I often end up using \dfrac for fractions in inline math, which are the kinds of fractions I might want to use tsf on later one).

A possible drawback of this would be that tsf stops being involutive: Once you apply it to a \dfrac you can only get back a \frac (at least not without 'manual work').

[lervag]

Is \dfrac a custom command or is it provided by a package?

[ces42]

Oh right, I forgot to mention it's from amsmath (so fairly standard I would say).

[lervag]

Sorry about taking so damn long here! No real excuse, except "life" and new issues getting priority for no good reason.