Rigify was recently added to the core add-ons, and is now
translatable. This change fixes many issues that made messages
poorly or not translatable.
- Replace f-strings and % formatting with str.format().
- Use iface_ and rpt_ to translate formatted strings.
- Rename metarig submenus from "<Category> (submenu)" to simply
"<Category>" to allow the menu entries and submenus to have the same
name and be translated. The label was awkward anyway in my opinion.
- Remove trailing "." in operator reports.
78b9218c98