Fix documentation of screen.icon to make it explicit that GIFs might

not work

appinventor/docs/learn/reference/components/basic.html

@@ -1244,10 +1244,10 @@
          An image to be used as the icon for the installed application on the phone. This
                   should be a PNG or a JPG image; 48x48 is a good size.
          <i>
-          Warning
+          Warning:
          </i>
-         : Specifying
-                  images other that PNG or JPG, for example .ico files, may prevent App Inventor
+          Specifying
+                  images other than PNG or JPG, for example GIF or .ico files, may prevent App Inventor
                   from being able to package the application.
         </dd>
         <dt>