Change PROCEDURE to FUNCTION in CREATE EVENT TRIGGER syntax

This was claimed to have been done in
0a63f996e0, but that actually only
changed the documentation and not the grammar.  (That commit did fully
change it for CREATE TRIGGER.)

src/backend/parser/gram.y

@@ -5578,7 +5578,7 @@ ConstraintAttributeElem:
 
 CreateEventTrigStmt:
 			CREATE EVENT TRIGGER name ON ColLabel
-			EXECUTE PROCEDURE func_name '(' ')'
+			EXECUTE FUNCTION_or_PROCEDURE func_name '(' ')'
 				{
 					CreateEventTrigStmt *n = makeNode(CreateEventTrigStmt);
 					n->trigname = $4;
@@ -5589,7 +5589,7 @@ CreateEventTrigStmt:
 				}
 		  | CREATE EVENT TRIGGER name ON ColLabel
 			WHEN event_trigger_when_list
-			EXECUTE PROCEDURE func_name '(' ')'
+			EXECUTE FUNCTION_or_PROCEDURE func_name '(' ')'
 				{
 					CreateEventTrigStmt *n = makeNode(CreateEventTrigStmt);
 					n->trigname = $4;

src/test/regress/expected/event_trigger.out

@@ -27,7 +27,7 @@ create event trigger regress_event_trigger on ddl_command_start
    execute procedure test_event_trigger();
 -- OK
 create event trigger regress_event_trigger_end on ddl_command_end
-   execute procedure test_event_trigger();
+   execute function test_event_trigger();
 -- should fail, food is not a valid filter variable
 create event trigger regress_event_trigger2 on ddl_command_start
    when food in ('sandwich')

src/test/regress/sql/event_trigger.sql

@@ -28,7 +28,7 @@ create event trigger regress_event_trigger on ddl_command_start
 
 -- OK
 create event trigger regress_event_trigger_end on ddl_command_end
-   execute procedure test_event_trigger();
+   execute function test_event_trigger();
 
 -- should fail, food is not a valid filter variable
 create event trigger regress_event_trigger2 on ddl_command_start