Add missing locale strings to FR locale

[nexdrew]

🇫🇷 Some strings were found to be previously missing from y18n lookup; this adds them to fr.json with an attempted French translation:

"Path to JSON config file": "Chemin du fichier de configuration JSON",
"Show help": "Affiche de l'aide",
"Show version number": "Affiche le numéro de version"

See related discussion in PRs #220 and #221.

@LoicMahieu If you have time, I would greatly appreciate a quick review of these French translations. Thanks!

[LoicMahieu]

Looks perfect 🚀
Just a remark not related specially to french language. It's about "JSON" or "json", we use the both "syntax" for describing the same thing. It would be good to harmonize ?
Personally I prefer the upper case.
/cc @bcoe

[nexdrew]

Thanks @LoicMahieu!

I agree there are some inconsistencies in the text that yargs outputs. Not only the treatment of "JSON" vs "json" (which should probably be upper-case, as you suggest), but also a couple error messages do not start with a capital letter.

I'll see what I can do to clean this up. Thanks again!

[nexdrew]

With commit 57af0ab, I made the following changes to address the inconsistencies in current locale strings:

• Change "json" -> "JSON" for relevant y18n keys and values for all locales
• Make sure all error messages start with a capital letter, including y18n keys and values for all locales

All tests so far look good. I will make sure the necessary changes are propagated to PR #224 for the Portuguese translation as well.

[nexdrew]

@bcoe My last change will "break" user code that attempts to customize the following 2 error message keys via updateLocale():

• "not enough arguments following: %s"
• "invalid json config file: %s"

"Break" meaning their code will no longer override the default messages, since the y18n keys have changed.

It seems we would either:

1. Stick with this change and bump major version when it is merged/released
2. Revert the key change and live with the inconsistency between keys and values

What is your preference?

[bcoe]

@nexdrew given how new this feature is, I think I'm comfortable making this a minor bump:

1. I doubt many consuming libraries have customized these strings.
2. I would argue slight copy edit could be considered a patch release -- I do think, as you've outlined, we should avoid it since it can be a hassle for upstream libraries.

Now that we have translations in for French and Spanish, feel free to cut a release 👍

Let's hold off on releasing Portuguese, @seldo would like to announce this translation as part of his talk at Brazil JS.

In other exciting news @sindresorhus is looking into creating a sync version of os-locale, so that we can automatically detect people's locale 💃

[nexdrew]

@bcoe Sounds good. I'll merge this as is and cut a 3.18.0 release today.

[nexdrew]

yargs@next now points to 3.18.0 😬

[nexdrew]

Ran a bunch of tests without problem. 3.18.0 is now yargs@latest. 😎

[bcoe]

@nexdrew \o/