shortcut_catcher: Fix KeyCommandMap::_DeleteHKSList()

You can't increment the list item counter as you delete because the count
decreases as you go. Instead delete the first item until there are no more
items, then delete the list.
shortcut_catcher: style overhaul
Revert "shortcut_catcher: Fix KeyCommandMap::_DeleteHKSList()"

This reverts commit cb3243fbbd1f06f5c205c7cbc3a6911586d6cf9e.

Sorry, this might do bad things.