Mk/Scripts: Add qa check for man pages

portmgr@ has been actively working on moving man pages from
${PREFIX}/man to ${PREFIX}/share/man. Majority of the ports belonging to
non-committers or aliases has been migrated to ${PREFIX}/share/man.
There are still around 1000+ ports remaining mainly from the committers.
portmgr@ has planned to make the hard change after the split of 2024Q3
after which ports that installs man pages in ${PREFIX}/man will no
longer build or will be BROKEN.

Approved by:	portmgr

Mk/Scripts/qa.sh

@@ -1034,10 +1034,21 @@ reinplace()
 	fi
 }
 
+prefixman() {
+	local manlist
+
+	manlist=$(find ${STAGEDIR}${PREFIX}/man -type f)
+	if [ -n "${manlist}" ]; then
+		warn "Installing man files in ${PREFIX}/man is no longer supported. Consider installing these files in ${PREFIX}/share/man instead."
+		ls -liTd ${manlist}
+	fi
+	return 0
+}
+
 checks="shebang symlinks paths stripped desktopfileutils sharedmimeinfo"
 checks="$checks suidfiles libtool libperl prefixvar baselibs terminfo"
 checks="$checks proxydeps sonames perlcore no_arch gemdeps gemfiledeps flavors"
-checks="$checks license depends_blacklist pkgmessage reinplace"
+checks="$checks license depends_blacklist pkgmessage reinplace prefixman"
 
 ret=0
 cd ${STAGEDIR} || exit 1