[css-position] Add issue about logical properties being out of date.

Author: fantasai

css-position/Overview.bs

@@ -984,6 +984,8 @@ Box offsets: 'top', 'right', 'bottom', 'left'</h3>
 <h3 id="logical-box-offsets-beaso">
 Logical box offsets: 'offset-before', 'offset-end', 'offset-after' and 'offset-start'</h3>
 
+  Issue: See [[!CSS-LOGICAL-1]]; this section is not up-to-date.
+
   Logical offset properties allow for offsetting positioned boxes based on the
   'writing-mode' and 'direction' properties. When both the physical property and
   equivalent logical property (based on 'writing-mode' and 'direction') are