[css-text-decor-4] Fix typo

Author: frivoal

css-text-decor-4/Overview.bs

@@ -44,7 +44,7 @@ by adding the ''trailing-spaces'' value.
 
   <pre class="propdef">
       Name: text-decoration-skip
-      Value: ''none'' | [ ''objects'' || [ ''spaces'' | [ ''leading-spaces'' || ''trailing-space'' ] ] || ''ink'' || ''edges'' || ''box-decoration'' ]
+      Value: ''none'' | [ ''objects'' || [ ''spaces'' | [ ''leading-spaces'' || ''trailing-spaces'' ] ] || ''ink'' || ''edges'' || ''box-decoration'' ]
       Initial: objects leading-spaces trailing-spaces
       Applies to: all elements
       Inherited: yes