Allow changing default click target from window<->application

[josefwells]

Description of the new feature

Other terminal tools, specifically wsltty/mintty allow you to change the modifier between shift/ctrl/alt/win/off and also to invert the sense by changing the default click target between window/application.

This would make using windows terminal (specifically WSL) with tmux more natural and more like a native linux environment (copy with highlight, paste with right-click.. not additional modifiers needed).

Proposed technical implementation details

No response