[KOpenWithDialog] Add generic name from .desktop files as a tooltip
Summary:
Extend the current setup by adding a tooltip based on the generic name
entry from the .desktop files.
This is especially useful for new users who don't know what each application
in the list can be used for.
CCBUG: 109016
Test Plan:
make && ctest
And a quick test of the openwith dialog, a tooltip is displayed for
most entries.
Reviewers: Frameworks, dfaure
Reviewed By: dfaure
Subscribers: kde-frameworks-devel
Tags: Frameworks
Differential Revision: https://phabricator.kde.org/D28371