Improve copywriting
Improve copywriting

Co-authored-by: Sandra Chakroun <1e3d1d967851893ec15a24bf1db4ec82f0dc8ac9@users.noreply.github.com>

openfisca/openfisca-doc,openfisca/openfisca-doc,openfisca/openfisca-doc,openfisca/openfisca-doc