set_locale_string
Description:
Associates a string value for key and locale under group_name.
If the translation for key cannot be found then it is created.
If locale is `C` then the untranslated value is set (since GLib 2.84).
Parameters:
| this |
a key file |
| group_name |
a group name |
| key |
a key |
| locale |
a locale identifier |
| string |
a string |