pgsql: doc: Document reopen of output file via SIGHUP in pg_recvlogical

doc: Document reopen of output file via SIGHUP in pg_recvlogical.

When pg_recvlogical receives a SIGHUP signal, it closes the current
output file and reopens a new one. This is useful since it allows us to
rotate the output file by renaming the current file and sending a SIGHUP.

This behavior was previously undocumented. This commit adds
the missing documentation.

Back-patch to all supported versions.

Author: Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
Reviewed-by: Shinya Kato <shinya11(dot)kato(at)gmail(dot)com>
Discussion: https://postgr.es/m/0977fc4f-1523-4ecd-8a0e-391af4976367@oss.nttdata.com
Backpatch-through: 13

Branch
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REL_13_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/ab13b7a8c7bcf6d543a8f87d55359cc0ad261157

Modified Files
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doc/src/sgml/ref/pg_recvlogical.sgml | 10 ++++++++++
1 file changed, 10 insertions(+)