Hide templates from the Control Panel selection

How do I hide templates from the list in the Control Panel?

If you are using templates for perch_content_custom you probably don’t want these cluttering the select list when setting up a region.

To hide templates from the list in the Control Panel, start the template name with an underscore. The following template will appear in the list:

my_custom_template.html

Rename it with an underscore at the start and it will not appear but still be accessible from perch_content_custom.

_my_custom_template.html