[css-ui-4] No need to list all in the list of ignorable properties

Only longhands have effects, so no need to say anything about
shorthands, as they get resolved before we worry about what has an
effect on what.

Author: frivoal

css-ui-4/Overview.bs

@@ -1907,7 +1907,6 @@ However, the following properties must not be disregarded:
 	<li>'margin' and related long-hand properties
 	<li>'unicode-bidi'
 	<li>'direction'
-	<li>'all' <span class=note>This does not imply a requirement to apply all the properties reset by 'all'</span>
 	<li>'cursor'
 	<li>'z-index'
 </ul>