Re-add `--parent-term-exit`

[dmgnr]

Is your feature request related to a problem? Please describe. I believe 75570648325e44a06438216f0eaf49c68e2da082 was not meant to delete parent-term-exit from the code.

Describe the solution you'd like Re-add pieces of code that made it happen.

Describe alternatives you've considered .bashrc based conditional exit

Additional context My current workaround is:

[ -f ~/.inshellisense/bash/init.sh ] && source ~/.inshellisense/bash/init.sh                                                                       
is                                                                                                                                                 
clear                                                                                                                                              
[ "$ISTERM" != "1" ] && exit