Update script_commands.txt

- Update instance_enter Description

doc/script_commands.txt

@@ -7485,7 +7485,7 @@ the script will come to a halt.
 
 ---------------------------------------
 
-*instance_enter("<instance name>");
+*instance_enter("<instance name>"{,<x>,<y>});
 
 Warps player to the specified instance after the script terminates. The map and
 coordinates are located in 'db/(pre-)re/instance_db.txt'.
@@ -7497,18 +7497,6 @@ The command returns 0 upon success, and these values upon failure:
 
 ---------------------------------------
 
-*instance_enter2("<instance name>",<x>,<y>);
-
-Warps player to the specified instance after the script terminates. The map 
-are located in 'db/(pre-)re/instance_db.txt'. Coordinates is <x> and <y>.
-
-The command returns 0 upon success, and these values upon failure:
- 1: Party not found.
- 2: Party does not have an instance.
- 3: Other errors (invalid instance name, instance doesn't match with party).
-
----------------------------------------
-
 *instance_npcname("<npc name>"{,<instance id>})
 
 Returns the unique name of the instanced script. If no ID is specified,