package: return from shellHook correctly

If our shellHook is being run from a nested nix-shell (see 7a12bc200¹),
then (I think) it is run from a bash function due to the nesting, then
`return` is correct. If its `eval`'d though, then there isn't really a
correct way to early exit. So we can just unconditionally be executed in
a function.

Basically, we have IIFE at home.

[1]: 7a12bc2007accb5022037b5a04b0e5475a8bb409

Change-Id: Iacad25cbbf66cde2911604e6061e56ad6212af7e

0 files changed, 0 insertions, 0 deletions