[css-navigation-1] Remove ISSUE that has been fixed.

This was fixed in 0b27f7c and (the
"missed edits" part of) fcd4631.

Author: dbaron

css-navigation-1/Overview.bs

@@ -475,9 +475,6 @@ if the following steps return true:
 				the provided URL pattern,
 				and the from or to URL of the current navigation.
 
-ISSUE: A <<link-condition>> should also be able to be a named route
-once those are added back to the spec.
-
 <h2 id="current-nav-urls">Current navigation URLs</h2>
 
 Both the ''@navigation'' rule and the '':link-to()'' pseudo-class