[css-position-3] Add missing comma in list of properties for definition group (w3c#7077)

Author: dontcallmedom

css-position-3/Overview.bs

@@ -482,7 +482,7 @@ Box Insets: the 'top', 'right', 'bottom', 'left', 'inset-block-start', 'inset-in
 	interact as defined in [[!CSS-LOGICAL-1]].
 	Values have the following meanings:
 
-	<dl dfn-for="top,right,bottom,left, inset-block-start,inset-inline-start,inset-block-end,inset-inline-end inset-block,inset-inline,inset" dfn-type="value">
+	<dl dfn-for="top,right,bottom,left, inset-block-start,inset-inline-start,inset-block-end,inset-inline-end,inset-block,inset-inline,inset" dfn-type="value">
 		<dt><dfn>&lt;length></dfn>
 		<dd>
 			The inset is a fixed distance from the reference edge.