CHARACTER may be a script name symbol. In that case, use FONT-SPEC
for all characters that belong to the script.
-CHARACTER may be a charset which has a :code-offset attribute and the
-attribute value is greater than the maximum Unicode character
-\(#x10FFFF). In that case, use FONT-SPEC for all characters in the
-charset.
+CHARACTER may be a charset. In that case, use FONT-SPEC for all
+characters in the charset.
FONT-SPEC may be:
* A vector [ FAMILY WEIGHT SLANT WIDTH ADSTYLE REGISTRY ].