landingpage: Fix "Most Used Pages" grid
landingpage: Set implicit size, so that kcmshell doesn't open too small
landingpage: Clean up a comment
ButtonGroup is good, ButtonGroup is needed, leave ButtonGroup alone.
landingpage: Clean up unused function
landingpage: Fix broken binding in "Most Used Pages" grid
First rule of the fighting club: never bind to a list. You never know what the heck you're up against.
On the other hand, assigning FormData.buddyFor in a procedural way in the Repeater's hook is robust, and there's nothing that could go wrong.
landingpage: Port "Most Used Pages" grid to Kirigami.SizeGroup
Even though SizeGroup is unpolished and to-be-redone, it is still better than hand-rolled implementation of O(n^2/2) custom property watcher.