Documentation for input settings

There is currently no documentation that explains the various configuration options for different input devices. Such documentation would be very helpful.

• Page/section that explains different device types
• Page/section for general input options
  • "Merge button events with stylus tip events"
  • Pressure Inference
  • Input stabilization
• Page/sections for device type-specific configuration options
  • Mouse
  • Pen / stylus
  • Touchscreen
• Create an "FAQ" of sorts describing common problems and their solutions

Use the checklist in the issue to define the documentation scope, starting with the sections on device types and general input options. Cover the listed mouse, pen/stylus, and touchscreen settings, then add the requested FAQ; the work is done when each checklist item has a corresponding documented section.