make LocaleMiddleware and APPEND_SLASH work better together

[benzkji]

want to redirect /foo AND /foo/ (obviously) to /bar/

whne LocaleMiddleware is enabled, together with i18n_patterns in urls.py, we'll have to enter two redirects, with and without slash - as /foo/ is not a valid url (as checked in CommonMiddleware, about here: https://github.com/django/django/blob/main/django/middleware/common.py#L71 ), and because of that, no redirect to /foo/ is made (but, instead, to /language/foo/).

One approach could be to check for Redirects with and without slash at the end, when there is no slash at the end of the current path. Or even try a "ignore the slash at the end" approach, making the final slah irrellevant. This would enhance usability for redirect editors, as currently, one is often forced to enter redirects with and withouth the trailing slahsh.

[benzkji]

PAINLESS_REDIRECTS_IGNORE_TRAILING_SLASH setting?