[pgpool-committers: 7689] pgpool: Doc: fix description about heartbeat_device.

[Tatsuo Ishii]

Doc: fix description about heartbeat_device.

It did not mention the parameter can only be used if Pgpool-II started
as root.

Branch
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V3_6_STABLE

Details
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https://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=667689cd9c5b89ba92d472e1977f2d02703ee82b

Modified Files
--------------
doc.ja/src/sgml/watchdog.sgml | 4 ++++
doc/src/sgml/watchdog.sgml    | 5 +++++
2 files changed, 9 insertions(+)