fix layout for chrome

resource/styles/scss/_editor-overlay.scss

@@ -35,8 +35,8 @@
 
   // cheat sheat
   .overlay.overlay-gfm-cheatsheet {
-    justify-content: end;
-    align-items: end;
+    justify-content: flex-end;
+    align-items: flex-end;
 
     pointer-events: none;