[css-overflow-4] Update references

Author: frivoal

css-overflow-4/Overview.bs

@@ -1003,7 +1003,7 @@ Forcing a Break After a Set Number of Lines: the 'max-lines' property</h3>
 		“column breaks” (breaks across multi-column layout columns [[css-multicol-1]]),
 		or “region breaks” (breaks across any other kind of CSS-induced <a>fragmentation containers</a>).
 
-		If an implementation supports neither [[CSS-REGIONS-1]] nor [[CSS-OVERFLOW-4#fragmentation]],
+		If an implementation supports neither [[CSS-REGIONS-1]] nor ''continue: discard'',
 		then it will have had no occasion yet to run into that kind of breaks,
 		and this will be an addition.
 		However the addition does not involve bringing over any of the [[CSS-REGIONS-1]] functionality.