Update usaco-923.mdx

Author: SansPapyrus683

solutions/silver/usaco-923.mdx

@@ -5,10 +5,14 @@ title: Painting the Barn
 author: Kevin Sheng, KJ Karaisz
 ---
 
-**Note:** This editorial assumes one already has a firm grasp of the
+<Warning title="Prior Knowledge">
+
+This editorial assumes one already has a firm grasp of the
 [silver](http://www.usaco.org/current/data/sol_paintbarn_silver_feb19.html)
 version of this problem.
 
+</Warning>
+
 <Spoiler title="Hint 1">
 
 Say FJ could only paint one rectangle of paint over the barn.