Entry function must not return any value (MystenLabs#4319)

I think there's a mistake here. This is because I know that entry functions cannot return any value. So, the create_monster_ function here is not an entry function.

doc/src/explore/prototypes.md

@@ -140,7 +140,7 @@ GET /object_info?objectId={{monster_id}}
     }
 
     // Creates a basic Monster object
-    public entry fun create_monster_(
+    public fun create_monster_(
         monster_name: vector<u8>,
         monster_img_index: u64,
         breed: u8,