[connection] provide some missing documentation bits
The previous changesets remove information about session data and transaction data.
We provide the necessary entries in the docstring of the Connection class.
Related to #3933480.
#! /bin/sh -e
if [ -x "/etc/init.d/cubicweb-ctl" ]; then
invoke-rc.d cubicweb-ctl restart || true
fi
#DEBHELPER#
exit 0