Not doing so caused crashes on applications which don't fall back to
English when a translation is missing.
We're adding them in a separate file so we can exclude it from crowdin
and so translators don't translate symbols as if they were words which
need translation.
Eventhough some of us sentimentals still like the syntax `to_not` the current trend is to move to the new syntax `not_to`.
In this commit we are updating the references of expectations that used `to_not` to `not_to`.
The same way we did for banners.
We needed to add new translation keys so the labels are displayed in the
correct language. I've kept the original `title` and `body` attributes
so they can be used in other places.
While backporting, we also added the original translations because they
hadn't been backported yet.
By doing so and including it in ActionDispatch::Routing::UrlFor, we make
it available in controllers, helpers and specs, and so we can remove the
duplication we had there with methods dealing with the same problem.
Even if monkey-patching is ugly, using a different module and executing
ActionDispatch::Routing::UrlFor.send(:include, MyModule) wouldn't make
the method available in the controller.
