tweak the language a bit

Author: benfry

build/shared/lib/welcome/index.html

@@ -64,7 +64,7 @@
     </p>
 
     <p style="margin-bottom: 5px;">
-      And when you're ready, visit Tools &rarr; Theme Selector to choose your own color scheme for the environment. Not fond of sketch_220809a? You can also select an alternate sketch naming method in the Preferences window.
+      Be sure to visit Tools &rarr; Theme Selector to choose your own color scheme for the environment. Not fond of sketch_220809a? You can also select an alternate sketch naming method in the Preferences window.
     </p>
 
   </body>