The use case for negating a keyset is very confusing, and can
lead to validators that don't do what they expect.
This commit introduces NonNegatable rules, which will throw
a Component exception if you try to wrap them in `Not`.
This change was necessary to ensure proper message reporting
when extra keys exist on the keyset.
This fixes#1349
The current documentation is hosted via GitHub pages rendered by
"Couscous". Every time we need a new version of the documentation
published we need to manually execute the "couscous".
This commit reorganize the documentation to be published to
"Read the Docs" because it will also allow us to have documentations per
version of the library most importantly provider a search field for the
documentation.
The documentation will be then published on:
https://respect-validation.readthedocs.io/
Signed-off-by: Henrique Moody <henriquemoody@gmail.com>
