[selectors] match_kwargs and match_form_params selectors both accept a new `once_is_enough` argument (closes #1990438)
also fix docstring of match_exception and references to selectors in the book.
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/devtools/ usr/lib/PY_VERSION/site-packages/cubicweb/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/skeleton/ usr/lib/PY_VERSION/site-packages/cubicweb/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/test usr/lib/PY_VERSION/site-packages/cubicweb/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/entities/test usr/lib/PY_VERSION/site-packages/cubicweb/entities/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/ext/test usr/lib/PY_VERSION/site-packages/cubicweb/ext/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/server/test usr/lib/PY_VERSION/site-packages/cubicweb/server/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/sobjects/test usr/lib/PY_VERSION/site-packages/cubicweb/sobjects/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/hooks/test usr/lib/PY_VERSION/site-packages/cubicweb/sobjects/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/web/test usr/lib/PY_VERSION/site-packages/cubicweb/web/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/etwist/test usr/lib/PY_VERSION/site-packages/cubicweb/etwist/