another bug: zsh_directory_name

[Oliver Kiddle <okiddle@xxxxxxxxxxx>]

Just thought I'd check that the case of calling this new ~[...] stuff
recursively had been handled. The following caused an instant seg fault:

zsh_directory_name() {
  echo ~[]
}

Out of interest what are people using this for. It seems like a nice
idea, but I've yet to think of an actual use that can't be done with a
normal named directory. Transformations on the current $PWD seem to be
one logical option - ${PWD/src/include} for instance. Or an easier syntax
for (../)#

Oliver