Add pt_BR strings

[ghost]

Hello dev,

I translated strings into pt_BR.

File: strings

Thanks

[eoineoineoin]

Thanks for that.

Do you think it is also useful to add training exercises for accented characters? According to Wikipedia there are some listed, but I'm not sure if those characters are transmitted, in practice? Notably, the list at that link doesn't have all the required accents -- there's no a acute or o circumflex, for example.

[ghost]

You're welcome.

For now I believe it's very good to get started with Morse, no doubt someone will request it in future.