$ function ouch
     exec fish
 end
$ ouch
There are still jobs active:

   PID  Command
     0  ouch

as described by @scorphus on gitter, and oh-my-fish/oh-my-fish#664.

This is caused by us checking for running jobs before doing exec now (1b1bc28), in conjunction with the hierarchical job changes.

I think we might just get away with warning only with background processes (i.e. those where is_foreground() is false). @mqudsi?

The obvious question is if this is important enough to warrant a 3.0.1, or a quick 3.1.