Agata Cacko authored Feb 09, 2020 and Raghavendra Kamath committed Feb 09, 2020

Before this commit, there was only information about getting
the backtrace from Krita on Windows in the manual.
This commit adds information:
- how to get a backtrace on Mac and Linux
- how to get a text output from Krita
- how to get a Krita usage log