[css-overflow-4] phrasing tweak

Adjust the order of the text to match the order of the grammar, in order
to avoid suggesting a different ordering.

See #8742

Author: frivoal

css-overflow-4/Overview.bs

@@ -927,13 +927,14 @@ Legacy compatibility</h4>
 		New Values: -webkit-legacy
 	</pre>
 
-	Like 'line-clamp', '-webkit-line-clamp' is a shorthand of 'max-lines', 'continue', and 'block-ellipsis',
+	Like 'line-clamp', '-webkit-line-clamp' is a shorthand of 'max-lines', 'block-ellipsis', and 'continue',
 	except that:
 
 	* its syntax is ''line-clamp/none'' | <<integer [1,∞]>>
-	* it sets 'continue' to ''continue/-webkit-legacy'' instead of ''collapse''
-	    (as if the ''line-clamp/-webkit-legacy'' keyword was set on 'line-clamp')
 	* it unconditionally sets 'block-ellipsis' to ''block-ellipsis/auto''
+	* it sets 'continue' to ''continue/-webkit-legacy'' instead of ''collapse''
+		when an <<integer [1,∞]>> is specified
+		(as if the ''line-clamp/-webkit-legacy'' keyword was set on 'line-clamp')
 
 	The <dfn value for=continue>-webkit-legacy</dfn> value behaves identically to ''collapse'',
 	except that it only takes effect