[rqlrewrite] Enhance detection of need for Exists node
We actually want one only if this is not a (`And` / `Or`) binary tree of `Not` or
`Exists` nodes, so write a recursive function to tell so.
Related to #17074119
.. -*- coding: utf-8 -*-
Writing text reports with RestructuredText
==========================================
|cubicweb| offers several text formats for the RichString type used in schemas,
including restructuredtext.
Three additional restructuredtext roles are defined by |cubicweb|:
.. autofunction:: cubicweb.ext.rest.eid_reference_role
.. autofunction:: cubicweb.ext.rest.rql_role
.. autofunction:: cubicweb.ext.rest.bookmark_role