[css-overflow-3] Clean up issues

Author: fantasai

css-overflow-3/Overview.bs

@@ -259,14 +259,10 @@ Scrollable Overflow</h3>
 			and that <a>scrollable overflow</a> is not already clipped
 			(e.g. by the 'clip' property or the 'contain' property).
 
-			Issue: should ''overflow: clip'' also clip the <a>scrollable overflow</a>
-			or should it remain a pure paint-time operation,
-			which would mean that scrollable overflow, while invisible, would still be scrollable.
-
 			Note: The 'mask-*' properties [[!CSS-MASKING-1]]
 			do not affect the <a>scrollable overflow area</a>.
 
-			Issue: Need to evaluate compat of honoring or ignoring 'clip' and 'clip-path'.
+			ISSUE(8607): Need to evaluate what should/should not clip [=scrollable overflow=].
 
 		<li>
 			Additional padding added