[Feature Request] Add option to force sync multiplier for supported displays (Variable Refresh Rate / Adaptive Sync)

[SaltyBet]

Like Low Framerate Compensation (LFC), but manually triggered.

Use case:

• Increased display fluidity perception.
• Reduced blurring.
• Exact FPS/Hz multiplier.

Ideally, able to set an arbitrary multiplier (2x, 3x, etc.), as long as the sync range of the display supports it.