NormalAngle = function (line)
{
    var angle = Angle(line) - MATH_CONST.TAU;

    return Wrap(angle, -Math.PI, Math.PI);
}
Get the angle of the normal of the given line in radians.

@function Phaser.Geom.Line.NormalAngle
@since 3.0.0

@param {Phaser.Geom.Line} line - The line to calculate the angle of the normal of.

@return {number} The angle of the normal of the line in radians.