[css-grid] Remove another solved issue.

Author: fantasai

css-grid/Overview.bs

@@ -2174,10 +2174,6 @@ Grid Definition Shorthand: the 'grid' property</h3>
 		</pre>
 	</div>
 
-	Issue: The auto-placed grid shorthand syntax isn't particularly useful.
-	An auto-placed grid needs an auto axis, but also an explicit axis.
-
-
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