Fix: generic locale fallback on all platforms when language is unavailable
Move the locale fallback chain out of the #ifdef __linux__ block so it
applies on macOS and Windows too. Add a base-language fallback step that
strips the region code (e.g. en_IL -> en) before trying the full
fallback chain (current locale, system, best, en_US, en_UK).
Previously, if wxLocale::IsAvailable() failed on non-Linux, the app
would show an error and exit. Now it gracefully falls back to a working
locale.
Co-authored-by: SoftFever <softfeverever@gmail.com>
Eyal Levin