custom input to add for location

### Is your feature request related to a problem? Please describe
Not really a problem but we made a custom input for "_address_region" and have been using this for our offices to up the zip code of their office so WPJM can sort them to pages for each of our locations. The problem is i have to go into the functions PHP and add "_addres_region" to line 99 for this work.

### Describe the solution you'd like
Either add "_address_region" to line 99, program a way to add it from the settings page, or give me an idea of how to do this from the child theme of my WP site

### Describe alternatives you've considered
Tried sorting by author but the jobs shortcode does not seem to support it.

### Additional context
https://personnelplusinc.com/jobs-boise-idaho/ and other Job Search pages to see how it is working. Would like a way for it not getting overridden with every update

Start by inspecting the functions PHP code around line 99 and the job shortcode behavior related to sorting. Compare the requested _address_region input with the existing custom-input handling, then determine whether the supported result should be a settings option or a child-theme extension that survives updates.

Written by the indexing model from the issue text.