add ent callout

Author: JEverhart383

content/concepts/users.mdx

@@ -44,6 +44,17 @@ The identifier for a user is important as it's the unique key that we will use t
   }
 />
 
+<Callout
+  emoji="⭐"
+  title="Please note:"
+  text={
+    <>
+      Here's a cool new enterprise feature related to user relationships with
+      accounts or tenants.
+    </>
+  }
+/>
+
 ### Required attributes
 
 The following attributes are required for each user you identify with Knock.