yet more key bindings - lack of same...

When ?i shows key bindings, at the end of each group (movement,
prefixes, general, game, debug) report any commands for that
group which don't have any key assigned.  Movement and prefixes
all have keys; they'd be pretty useless without and key bindings
won't override movement commands. For general, the "keyless" are
|#exploremode
|#herecmdmenu
|#therecmdmenu
after this adds the relevant flag to their command definitions;
for game, "#terrain" is the only one; the debug section has 20.

There is a known problem that I've going to pretend that I didn't
notice:  if I use BIND=D:takeoffall then 'A' becomes unassigned,
'D' invokes #takeoffall, "#droptype" becomes keyless, and ?i
reports those correctly.  But if I use BIND=M:takeoffall, 'A'
becomes unassigned, 'M' continues to be its usual prefix, and
the "#takeoffall" command is nowhere to be seen.  The code that
tracks assignments is letting that case fall through the cracks.
'M' ends up assigned to both and the ?i code deliberately only
shows the first.

doc/fixes37.0

@@ -1,4 +1,4 @@
-NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.380 $ $NHDT-Date: 1607471879 2020/12/08 23:57:59 $
+NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.381 $ $NHDT-Date: 1607591199 2020/12/10 09:06:39 $
 
 General Fixes and Modified Features
 -----------------------------------
@@ -645,6 +645,9 @@ reading blessed scroll of teleportation confers one-shot teleport control
 mild zombie apocalypse
 list lamps and lanterns in charging prompt
 let tourists read conical hats
+when "?i" (show key bindings) displays commands and their keys, also show
+	commands without any key (so useable via '#', or possibly menu, only;
+	the majority are debugging commands)
 
 
 Platform- and/or Interface-Specific New Features