menuconfig: improive help text a bit

Suggested-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/kconfig/mconf.c

@@ -74,7 +74,7 @@ static const char mconf_readme[] = N_(
 "\n"
 "   Shortcut: Press <H> or <?>.\n"
 "\n"
-"o  To show hidden options, press <Z>.\n"
+"o  To toggle the display of hidden options, press <Z>.\n"
 "\n"
 "\n"
 "Radiolists  (Choice lists)\n"