kicking and killing an unseen monster

<Someone> reported that kicking [unlike hitting] an unseen monster
to death would leave an "I" on the screen.  This was due to a missing
DEADMONSTER check.  I also noticed that code to avoid leaving an extra "I"
behind when a monster jumps of of the way was only half right, resulting in
an extra "I" anyway.

doc/fixes34.1

@@ -152,6 +152,7 @@ Cancelled while polymorphed and Unchanging should provide feedback
 stone to flesh on a statue with contents would lose the contents if a
 	monster was on the same location as the statue
 steed movement would use your speed if walking step by step
+kicking a known, unseen monster would sometimes leave behind an extra I symbol
 
 
 Platform- and/or Interface-Specific Fixes