pgsql: doc: Fix primary status update WAL position description

doc: Fix primary status update WAL position description

Commit 5f3a49abf7f changed the primary status update message to report the
end of the last inserted WAL record instead of the WAL write position.
However, the protocol documentation still described the WAL position field as
the latest WAL write position, which no longer matches the message sent by
walsender.

Update the description of the WAL position field to indicate the end of the
last inserted WAL record, matching the implementation.

Author: Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
Reviewed-by: Ayush Tiwari <ayushtiwari(dot)slg01(at)gmail(dot)com>
Discussion: https://postgr.es/m/CAHGQGwFn2QfpHDR6cWxd98tqNb5vyguEis8rtqnqidFR36p4QQ@mail.gmail.com
Backpatch-through: 19

Branch
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REL_19_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/5a8cacfe5cb15d97d7f6aad022bde908b3ae8890

Modified Files
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doc/src/sgml/protocol.sgml | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)