* doc/lispref/display.texi (Low-Level Font): Mention what the data
types the font attributes are (bug#14634).
@itemx :slant
@itemx :width
These have the same meanings as the face attributes of the same name.
-@xref{Face Attributes}.
+@xref{Face Attributes}. @code{:family} and @code{:foundry} are
+strings, while the other three are symbols. As example values,
+@code{:slant} may be @code{italic}, @code{:weight} may be @code{bold}
+and @code{:width} may be @code{normal}.
@item :size
The font size---either a non-negative integer that specifies the pixel