Incorrect locale code for Brazilian Portuguese

[rossellhayes]

Available Locales lists br as the language code for Brazilian Portuguese, but that is the ISO 639-1 code for Breton. Brazilian Portuguese should be assigned the code pt_BR.

[tiesont]

Fair enough. Not sure when I'll have time to adjust this, but it does make sense to use the correct ISO code.

Pull-requests are welcome, as well.

[tiesont]

This will be corrected/updated in v6, which I hope to release soon.

[tiesont]

Closed in #820.

Please note that I've normalized the locale codes to what I see in the IANA list, so the new locale would be pt-BR.