[css-round-display] Add issue (ACTION-714: https://www.w3.org/Style/CSS/Tracker/actions/714)

Author: Jihye Hong

css-round-display/Overview.bs

@@ -338,3 +338,6 @@ What value does the percentage value of the 'polar-distance' property refer to?
 <p class="issue">
 Will an element (or a child) itself be rotated through the 'polar-angle' property?
 </p>
+<p class="issue">
+How to position items to the edge of the containing block without overflowing it? ( 'polar-anchor' is suggested)
+</p>