if we fail on this, everything below is dead code.

but imo, this should not fail. rather, it should detect at some point that the locale we are asking for is falling back to the locale we already have, and then simply do nothing at all (neither reset the document, nor change the locale or anything). i guess before this PR, we would reload the translation in this situation, which might destroy data if we have an unlucky situation.

the thing i was expecting we would want to fail is that if we findTranslation 'en' and then again bindTranslation 'de' that document (even though there already is a german translation) there would be an exception.