Fix typo in message

I introduced the typo in source code in the course of 75445c1515.
Repair.

src/backend/commands/subscriptioncmds.c

@@ -231,7 +231,7 @@ parse_subscription_options(List *options, bool *connect, bool *enabled_given,
 					(errcode(ERRCODE_SYNTAX_ERROR),
 			/*- translator: both %s are strings of the form "option = value" */
 					 errmsg("%s and %s are mutually exclusive options",
-							"slot_name = NONE", "enable = true")));
+							"slot_name = NONE", "enabled = true")));
 
 		if (create_slot && create_slot_given && *create_slot)
 			ereport(ERROR,

src/test/regress/expected/subscription.out

@@ -53,7 +53,7 @@ ERROR:  connect = false and enabled = true are mutually exclusive options
 CREATE SUBSCRIPTION testsub2 CONNECTION 'dbname=doesnotexist' PUBLICATION testpub WITH (connect = false, create_slot = true);
 ERROR:  connect = false and create_slot = true are mutually exclusive options
 CREATE SUBSCRIPTION testsub2 CONNECTION 'dbname=doesnotexist' PUBLICATION testpub WITH (slot_name = NONE, enabled = true);
-ERROR:  slot_name = NONE and enable = true are mutually exclusive options
+ERROR:  slot_name = NONE and enabled = true are mutually exclusive options
 CREATE SUBSCRIPTION testsub2 CONNECTION 'dbname=doesnotexist' PUBLICATION testpub WITH (slot_name = NONE, create_slot = true);
 ERROR:  slot_name = NONE and create_slot = true are mutually exclusive options
 CREATE SUBSCRIPTION testsub2 CONNECTION 'dbname=doesnotexist' PUBLICATION testpub WITH (slot_name = NONE);