Getting rid of WPS Office registry leftovers after uninstallation

Question

I have downloaded and installed WPS Office to test it and see if it is good for my needs but it wasn't. So i uninstalled it (using the control panel's program and features). however i still see some leftovers in some places like this one:

I believe that this is related to the registry, however i know that i should not mess with the registry without instructions (i have changed some registry keys previously while following detailed instruction)