Sets the function which is used to translate the contexts user-visible strings, for `--help` output.
If func is null, strings are not translated.
Note that option groups have their own translation functions, this function only affects the parameter_string (see
OptionContext), the summary (see
set_summary) and the description (see
set_description).
If you are using gettext, you only need to set the translation domain, see
set_translation_domain.
| this | |
| func |
the TranslateFunc, or null |
| data |
user data to pass to |
| destroy_notify |
a function which gets called to free |