- save_settings is semidet
- save_settings(+File) is semidet
- Save modified settings to File. Fails silently if the settings file
cannot be written. The save_settings/0 only attempts to save the
settings file if some setting was modified using set_setting/2.
- Errors
- -
context_error(settings, no_default_file) for save_settings/0
if no default location is known.