Invalid HTTP method will raise I18n::InvalidLocale if :en is not a valid locale.

Request#check_method uses to_sentence(locale: :en), which raises I18n::InvalidLocale when I18n.available_locales does not include :en and I18n.enforce_available_locales is true (default).

I inlined the to_sentence functionality in check_method to solve this. Not sure if this is the best solution, but it works.

**NOTE:** ActionController::MethodNotAllowed has a similar problem, but I don't know where that is tested or if it's even used anywhere.