Bug 425921

SUMMARY
When you are in a settings window, and you click on the "Help" button in the lower right corner, the web  browser that pops up has a 404, page nbot found, error

STEPS TO REPRODUCE
1. Click Kdenlive's "Settings" main menu item
2. Click "Configure Kdenlive..."
3. Click on the "Help" button in the lower right hand corner of trhe settings window.

OBSERVED RESULT
A web browser opens up, but it can'r load the help page. It has a 404 error. It is trying to load the following URL: https://docs.kde.org/stable5/en/kdemultimedia/kdenlive//kdenlive/index.html

EXPECTED RESULT
I expect to see a help document.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
Note, this is running on Debian Linux, which is running on an up to date Chromebook. All other Kdenlive's features appear to run correctly.