Add button to change modifier key from Shift to Ctrl-Shift / Cmd-Shift in preferences

[felixvd]

When I edit text, I often end up deleting things by accident, because the Shift button selects text passages that I then type over. I've changed the hotkey manually in the past, but it would be convenient if there was a "Use Ctrl-Shift or Cmd-Shift instead of Shift to look up text" button in the options. I wanted to do it myself, but I don't know how to deal with Qt, and I know I will never get around to it now.

Thanks for considering it and for Yomichan, it is the shit.