[css-flexbox] Make propdef table more useful.

Author: fantasai

css-flexbox/Overview.bs

@@ -1498,6 +1498,10 @@ The 'flex' Shorthand</h3>
 	<pre class='propdef shorthand'>
 	Name: flex
 	Value: none | [ <<'flex-grow'>> <<'flex-shrink'>>? || <<'flex-basis'>> ]
+	Initial: none
+	Applies to: <a>flex items</a>
+	Inherited: no
+	Media: visual
 	</pre>
 
 	The 'flex' property specifies the components of a <dfn>flexible length</dfn>: