face* uses deprecated mzlib/kw

[LiberalArtist]

Currently face* from pict/face is implemented with lambda/kw from the deprecated mzlib/kw, which is not compatible with #lang racket's keyword arguments.

I hope it would be ok to port pict/face (which actually re-exports the apparently undocumented module texpict/face) to modern Racket, and I would be happy to do that, but I don't know what the compatibility considerations are. If pict/face can't change, it seems important to note the non-standard calling convention in the documentation. (You can work around the current problem by writing e.g. (face* 'worried 'grimace 'frown '#:teeth? #t), where the keyword is quoted as an expression, which wouldn't work if pict/face used #lang racket.)

Additionally, looking at the implementation of face* revealed that only the first three by-position arguments are actually required: whatever the resolution to the keyword issue, this should be corrected in the documentation at the same time.

[rfindler]

What about making the face function accept a keyword argument for each of those things (eyebrow-kind, mouth-kind, etc) and the mood argument determines what the default values for those optional keyword arguments are?

Then we don't really need face* at all and we can adjust the docs to deprecate it?