fix: log error when Intl.PluralRules error

[zatteo]

When using i18next in an environment where Intl and Intl.PluralRules are not available we need to polyfill them.

When using intl and intl-pluralrules package, we also need to include locale data for the language we want like intl/locale-data/jsonp/fr.js (see here). If we do not do it, pluralization will fail silently and we will only get a no plural rule found for: fr warn log.

In this PR, I add a new log in the catch where we try to get the PluralRules. It helps debugging. It allowed to display a new and more explicit No locale data has been provided warn log in my case .

Checklist

• only relevant code is changed (make a diff before you submit the PR)
• run tests npm run test
• tests are included
• commit message and code follows the Developer's Certification of Origin

Checklist (for documentation change)

• only relevant documentation part is changed (make a diff before you submit the PR)
• motivation/reason is provided
• commit message and code follows the Developer's Certification of Origin

[adrai]

will be added in the next release

[coveralls]

coverage: 96.197%. remained the same
when pulling 604618a on zatteo:improve-logging
into da6d654 on i18next:master.