[autoform] Fix display_fields handling
This follows-up on changeset b2ceb483e056 (present in 3.25 as well), in
which AutomaticEntityForm.editable_attributes() was turned into a
generator. In this method, in case display_fields is not None, we
previously returned a list of (rtype, role); this was changed into a
yield, but the change was missing a return after the loop in order not
to go through the remainder of the function.
Add tests for editable_attributes() method.
^build$
^dist$
\.egg-info$
^.tox$
^.cache$
\.pyc$
\.pyo$
\.bak$
\.old$
\~$
\#.*?\#$
\.swp$
^doc/book/en/apidoc$
\.old$
\.pybuild
cubicweb/server/test/data/slapd.conf
debian/python-cubicweb
debian/*.log
debian/*.substvars
debian/cubicweb-doc
debian/cubicweb
debian/files
syntax: regexp
.*/data.*/database/.*
.*/data/ldapdb/.*
.*/data/uicache/
.*/data/libpython/cubicweb_.*/i18n/.*\.po
^doc/html/
^doc/doctrees/
^doc/book/en/devweb/js_api/
^doc/_build
^doc/js_api/
test-results.xml
ve