category for selecting a font. Currently, only lilypond's system
fonts (Emmentaler) are using this property. Available
values are @code{fetaMusic} (Emmentaler), @code{fetaBraces},
-@code{fetaNumber} (Emmentaler), and @code{fetaDynamic} (Emmentaler).")
+@code{fetaText} (Emmentaler).")
(font-family ,symbol? "The font family is the broadest category
for selecting text fonts. Options include: @code{sans},
@code{roman}.")