Dot-delimited translation key (e.g. "app.title").
OptionallangOverride: Language | ParamsExplicit Language code or a Params object (when called with two arguments where the second is an object, it is treated as params).
Optionalparams: ParamsOptional template parameters that replace {{placeholder}} tokens.
The resolved string, or the key itself if no translation is found.
Resolve a translation key to a localised string.