[donc] Fix building the cubicweb js documentation Avoids errors such as: Exception: Bad file id cubicweb.lazy referenced in INDEX_IN_ORDER in ../../../doc/tools/pyjsrest.py, fix this please

# copyright %(year)s %(author)s, all rights reserved.
# contact %(author-web-site)s -- mailto:%(author-email)s
#
%(long-license)s
"""%(distname)s entity's classes"""