Blender UI Layout API allows supplying parameters to operators via
button definitions. If an operator behavior strongly depends on its
parameters, it may be difficult to write a tooltip that covers all
of its operation modes. Thus it is useful to provide a way for the
operator to produce different descriptions based on the input info.
Reviewers: campbellbarton
Differential Revision: https://developer.blender.org/D5709
9ecbd67dfb