Update api-users.md

Seems like some words were missing in the opening description so I have tried to add them to make more sense :-)

Author: BatJan

16/umbraco-cms/fundamentals/data/users/api-users.md

@@ -1,5 +1,5 @@
 ---
-description: This guide will explain the API Users concept and how they differ from regular Users how to define
+description: This guide will explain the API Users concept and how they differ from regular Users and how to define them
 ---
 
 # API Users