It's a minor annoyance when you forget you can't do this in vanilla and
then get relocated somewhere random on the level. Since it's not a
harmful "trap", just allow the adventurer to teleport directly onto it.
Inadvertently reintroduced in f9f1236. It was just the conditional
that was bad: due to resolving the possible buffer underflow when
comparing to "muskox", the pluralizer now only adds -es when the length
of the string is greater than 5. So for "box" and "fox" the pluralizer
will never add the -es ending, since they are greater than 5.
This commit checks for "does not end in muskox" correctly.