[css-ui-3] Fix typo

Author: frivoal

css-ui/Overview.bs

@@ -307,7 +307,7 @@ Inherited: no
 Percentages: N/A 
 Media: visual 
 Computed value: absolute length; ''0'' if the outline style is ''outline-width/none''. 
-Amination type: <a href="https://drafts.csswg.org/css3-transitions/#animtype-length">length</a> 
+Animation type: <a href="https://drafts.csswg.org/css3-transitions/#animtype-length">length</a>
 </pre>
 
 <h3 id="outline-style">Outline Patterns: the 'outline-style' property</h3>