[css-fonts-4] allow aliases in font matching, fix #5819

Author: svgeesus

css-fonts-4/Overview.bs

@@ -3368,7 +3368,9 @@ if all font style properties were set to their initial value.
 
 	3. For other family names, the user agent attempts to find the
 		family name among fonts defined via ''@font-face'' rules and then
-		among available installed fonts, matching names with a
+		among available installed fonts
+		(this may include font aliases),
+		matching names with a
 		[[#localized-name-matching]] as outlined
 		in the section above.
 		If the font