Revise `text-font` to not take a `font-family` parameter

[blerner]

[schanzer]

How is this different from using text-font with courier as the font?

[blerner]

When I looked at the implementation, I thought I saw it said we ignored faces because they were system dependent... In any case, our documentation about text-font is woefully lacking then, because I didn't know we could handle this :)

[schanzer]

We ignore font-family, not font-face, due to old browser bugs (which may no longer be an issue). IIRC, CSS treats font-face as a superset of font-family, which means it's pointless to have them as two separate arguments to the function. I kept things consistent with Racket in WeScheme for obvious reasons, but we don't have that constraint in Pyret.

[blerner]

ok, I'll close this, and make it a docs issue

[blerner]

Actually, no -- let's take this opportunity to fix text-image to eliminate the font-family field.