Gamma 2.2 transfer function, common in CRT displays.
The Gamma 2.2 transfer function applies a simple power-law relationship between the input signal and the output luminance.
Both its inputs and outputs are normalized to [0, 1], similar to TransferFunction.BT1886 and TransferFunction.Gamma22 EOTFs.
Unity uses this EOTF when the ColorGamut of the display is ColorGamut.P3D65G22.