[pylint] remove abstract-method warning
This kind of message is targeted:
"Method 'entity_call' is abstract in class 'EntityView' but is not overridden (abstract-method)"
For now, only "entity_call" and "render_body" are dealt with, the list can be extended.
../../doc/book usr/share/doc/cubicweb-documentation
../../doc/_build/html usr/share/doc/cubicweb-documentation