pgsql: Document pg_ls_*dir hiding of directories and special files

Document pg_ls_*dir hiding of directories and special files

It's strange that a directory-listing function does not list all entries
in a directory, so let's at least document it. This involves

pg_ls_logdir
pg_ls_waldir
pg_ls_archive_statusdir
pg_ls_tmpdir

Backpatch as far back as it applies cleanly (and as far as as each
function exists). REL_10_STABLE uses different wording, but hopefully
people are not reading docs so old to write new apps anyway.

Author: Justin Pryzby <pryzby(at)telsasoft(dot)com>
Discussion: https://postgr.es/m/20200305161838.GJ684@telsasoft.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/8b6d94cf6c8319bfd6bebf8b863a5db586c19c3b

Modified Files
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doc/src/sgml/func.sgml | 4 ++++
1 file changed, 4 insertions(+)