improved documentation about maco.check.update.sh' --web option

work related to [https://bugzilla.ipr.univ-rennes.fr/show_bug.cgi?id=3947]

cluster/maco.check.update.sh

@@ -458,7 +458,7 @@ if [ ! "${NBARGS}" -eq "0" ]; then
 			URGENT_ONLY_MODE=0
 			;;
 		-w|--web )      ## Web mode
-			## Get versions from webserver
+			## Get maco versions from webserver https://store.ipr.univ-rennes.fr instead of sshfs mount /mnt/store.ipr
 			WEB_MODE=0
 			;;
 		-- )            ## End of options list