Preview: Set locale back when completed

[ryonakano]

Fixes #248

This issue is because reload_languages () calls Intl.setlocale (), which affects the execution of all locale-sensitive C library functions as written in valadoc:

The modifications remain in effect and influences the execution of all locale-sensitive C library functions until the next call to setlocale. If locale is a null pointer, setlocale queries the current C locale without modifying it.

W call Gnome.Languages.get_country_from_locale () in reload_formats () to construct the formats dropdown, and we pass null as the second parameter translation. Gnome.Languages.get_country_from_locale () calls setlocale() to retrieve the current value of LC_MESSAGES if translation is null. Here, LC_MESSAGES is affected by Intl.setlocale () in reload_languages ().

[vjr]

Code looks good, fixes the issue for me with English, India region and format, thanks.