[css-highlight] No restriction on static ranges accros containment boundaries

See #4598

Author: Florian Rivoal

css-highlight-api-1/Overview.bs

@@ -570,23 +570,6 @@ Range Updating and Invalidation</h3>
 	is not <a spec=dom for="StaticRange">valid</a>,
 	the user agent must ignore that [=range=].
 
-	Issue(4598): The interaction of {{StaticRange}}s in a [=custom highlight=]
-	and [[css-contain-2]]
-	seems problematic:
-	on a fully contained element,
-	you should expect that DOM changes to descendants of that element
-	will not cause invalidation and restyling/repainting
-	of elements outside the contained one.
-	However, if a static range has a boundary point inside the contained subtree
-	and another boundary point outside of it,
-	and the DOM in the contained subtree is changed
-	so that the boundary point inside no longer points to a valid node,
-	the whole range should be ignored,
-	which would affect painting outside the contained subtree.
-	Is this a weakness of [=style containment=],
-	or of the invalidation logic above,
-	or something else?
-
 <h2 id=events>
 Event Handling</h2>