mention msg_window in the Guidebook and long online help. I didn't update
hh since that only has one-liners. Also made the msg_window default clear
in the Guidebook and opthelp. Plus, an update to Guidebook.txt in hopes
that it won't need another before release.
- various commands were missing from various help files
- fix a few inconsistencies between similar help files
- M-2 doesn't do #twoweapon when number_pad is enabled
- M-? usually displays #? help info
- weasel-word the reason the screen shown in the Guidebook looks little like
several windowports
- document the playersuffix syntax in the nethack.6 man page
