kcms/cursortheme: migrate and unify docbook for cursor theme and launch feedback from plasma-desktop
The recent merge of the launch feedback into the cursor theme config didn't reflect this change in the documentation.
Integrate the contents of the launch feedback docbook into the cursor theme docbook, and move the docbook source from plasma-desktop to plasma-workspace where the KCM itself is.
Also overhaul the whole text a little and add more screenshots.
See also plasma-desktop!1365 (merged).
Edited by Natalie Clarius