idle-in-transaction timeout error does not give a hint

idle-in-transaction timeout error closed the session. I think in this
case the error message should give a hint something like other errors
(for example ERRCODE_CRASH_SHUTDOWN or
ERRCODE_T_R_SERIALIZATION_FAILURE) to ask users to reconnect.
Attached patch does that.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index a3b9757565..c3e4380603 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -3138,7 +3138,9 @@ ProcessInterrupts(void)
         if (IdleInTransactionSessionTimeout > 0)
             ereport(FATAL,
                     (errcode(ERRCODE_IDLE_IN_TRANSACTION_SESSION_TIMEOUT),
-                     errmsg("terminating connection due to idle-in-transaction timeout")));
+                     errmsg("terminating connection due to idle-in-transaction timeout"),
+                     errhint("In a moment you should be able to reconnect to the"
+                             " database and repeat your command.")));
         else
             IdleInTransactionSessionTimeoutPending = false;