[pkg] Fix extra packages not installable For instance `pip install -e ".[pyramid]"` should install the pyramid dependencies. A typo caused all these extra packages to not be found by pip. Closes #16121322.

usr/lib/python2*/*-packages/cubicweb/web
usr/lib/python2*/*-packages/cubicweb/wsgi
usr/share/cubicweb/cubes/shared/data
usr/share/cubicweb/cubes/shared/wdoc