Fixed #22812 -- Refactored lookup API documentation.

Thanks Anssi and Tim for reviews.
Fixed #22223 -- Prevented over-escaping URLs in reverse()

And follow more closely the class of characters defined in the
RFC 3986.
Thanks Erik van Zijst for the report and the initial patch, and
Tim Graham for the review.
Fixed #22351 -- Removed usage of lambdas in model field options.

Thanks claudep for review.
Fixed #13794 -- Fixed to_field usage in BaseInlineFormSet.

Thanks sebastien at clarisys.fr for the report and gautier
for the patch.