[css-fonts-4] fix #2505 value of font-style: normal vs. oblique 0deg;

Author: svgeesus

css-fonts-4/Overview.bs

@@ -629,7 +629,9 @@ Font style: the 'font-style!!property' property</h3>
     Inherited: yes
     Percentages: n/a
     Computed value: the keyword specified, plus angle in degrees if specified
-    Animation type: by computed value type
+	Animation type: by computed value type;
+	'normal' animates as 'oblique 0deg'
+	<!-- https://github.com/w3c/csswg-drafts/issues/2505 -->
     </pre>
 
     The 'font-style!!property' property allows italic or oblique faces to be selected.