Pretty printed trigger in psql

Psql shows too many parentheses when it prints triggers with WHEN clause.

postgres=# \d t1
Table "public.t1"
Column | Type | Modifiers
--------+---------+-----------
c1 | integer |
Triggers:
mytrig AFTER UPDATE ON t1 FOR EACH ROW
WHEN ((old.c1 <> new.c1)) EXECUTE PROCEDURE myfunc()
^ ^

The attached patch eliminates unneeded parentheses by using
pg_get_triggerdef(pretty = true) in psql.

Triggers:
mytrig AFTER UPDATE ON t1 FOR EACH ROW
WHEN (old.c1 <> new.c1) EXECUTE PROCEDURE myfunc()

I think this change is harmless because we don't use
pg_get_triggerdef(pretty = true) in any programs, including pg_dump.

Is this change ok?

Regards,
---
Takahiro Itagaki
NTT Open Source Software Center