crystal balls and space key

Another buglist entry.

<Someone> wrote:
- There appears to be no way to detect ghosts-and-shades; the
  space key just "Never mind"s. (Not that they'd be particularly
  visible on the resulting screen under ASCII, unless you've
  changed the 'monsters' option.)

Allow space; display results in inverse using detected_mon_to_glyph()

doc/fixes34.3

@@ -55,6 +55,9 @@ don't silently interrupt monster's hold on you if Levitation/Flying ends
 	while over water
 you could specifiy '~' with crystal ball and have it try to detect monsters, 
 	but it never revealed anything; show the entire long worm now
+allow a crystal ball to detect ghosts-and-shades via space key,  and display
+	the results using detected_mon_to_glyph() so that they show up in 
+	inverse video
 
 
 Platform- and/or Interface-Specific Fixes