[entity/url publishing] fetch_rqlst should use 'is_instance_of' instead of 'is'
We usually want to get any subclasses as well (think Training subclass of
Workcase). Closes #3210365.
Document: cubicweb-doc
Title: CubicWeb documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/cubicweb-documentation/index.html
Files: /usr/share/doc/cubicweb-documentation/*.html