More protocol.h replacements this time into walsender.c

When Who What
2025-07-23 15:41:07 Nathan Bossart (bossartn) Closed in commitfest PG19-1 with status: Committed
2025-07-23 15:41:07 Nathan Bossart (bossartn) Moved from CF PG19-2 to CF PG19-1
2025-07-23 01:11:55 Nathan Bossart (bossartn) New status: Ready for Committer
2025-07-23 01:11:53 Nathan Bossart (bossartn) Added bossartn as committer
2025-07-23 01:11:51 Nathan Bossart (bossartn) Added bossartn as reviewer
2025-07-23 01:11:50 Nathan Bossart (bossartn) Attached mail thread CADK3HH+owWVdnbmWH4NHG8=+kXA_wjsyEVLoY719iJnb=+tT6A@mail.gmail.com
2025-07-23 01:11:49 Nathan Bossart (bossartn) Created patch record