cleanup up #vanquished output

cleanup up #vanquished output

Tidy the output from disclosure of vanquished monsters at end of game
or from #vanquished wizard-mode command.  Instead of

Juiblex
The Wizard of Yendor (twice)
a mastodon
3 purple worms
an erinys
120 gnomes
42 grid bugs

it will line up the monster type names, yielding

    Juiblex
the Wizard of Yendor (twice)
  a mastodon
  3 purple worms
 an erinys
120 gnomes
 42 grid bugs

For short lists, the original looked ok (maybe even better...), but
for long lists at the end of a long game, aligning the names looks
better and is easier to read than left justifying everything.