more buglist crystal ball detection

more buglist crystal ball detection

<Someone> wrote:
- If I set the 'boulder' option, shouldn't I be able to give the
  symbol I define for them at the crystal ball "object or
  monster symbol" prompt and have it work?
- Could ']' be added as a synonym for 'm', as with genocide?
- set boulder symbol to '3'; use '/' or ';' to examine a
  boulder. Result is "unknown creature causing you disquiet
  co-located with a boulder" even though there's no warning
  glyph '3' there.