fix [part of] #H2554 - hunger when declining to attack peaceful monst

Reported last December by <email deleted>, attempting to move
into a peaceful monster's position and then declining to attack at the
confirmation prompt uses no time, as expected, but does burn nutrition
the same as if you carried out the attack.  A player could abuse that to
make room to eat an intrinisic-conferring corpse before it rots away.
This fixes that, and also makes attacking a monster via applying a polearm
and via kicking burn the same extra nutrition as ordinary attack.  I didn't
add it for attacking via throwing.

     He/she also reported that kicking at a peaceful monster and declining
to attack at the prompt wakes up nearby monsters even though no actual kick
ultimately takes place.  I can confirm that, but this does not fix it.

include/extern.h

@@ -802,6 +802,7 @@ E int FDECL(cant_squeeze_thru, (struct monst *));
 E boolean FDECL(invocation_pos, (XCHAR_P,XCHAR_P));
 E boolean FDECL(test_move, (int, int, int, int, int));
 E void NDECL(domove);
+E boolean NDECL(overexertion);
 E void NDECL(invocation_message);
 E boolean FDECL(pooleffects, (BOOLEAN_P));
 E void FDECL(spoteffects, (BOOLEAN_P));