Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -20,7 +20,7 @@ By submitting code you agree to the [LICENSE](https://github.com/vhf/free-progra
 
 4. We prefer small commits rather than one large commit in a pull request. If you don't have the time to make small commit, add an issue with all the links included and we'll add them for you.
 5. Use our standard for formatting the .md file. Check it out: [Formatting](#formatting)
-6. Please try to use alphabetic order.
+6. Must use ***alphabetic*** order.
 
 
 ### Formatting