[QGIS-Developer] Help guide for Processing Models

[matteo]

Hi devs,

Processing dialogs have no more the Help tab. If you create a model, as
for QGIS 2, you can add a short guide for the model.

The short description appears correctly in the right side of the dialog
while the single parameter description seems not available anymore (it
was in the Help tab).

Am I missing some step?

Thanks

Matteo