feat: add TwoPassDoubleSide

See: mrdoob/three.js#25165

also add doc comment of Side

Author: 0b5vr

types/three/src/constants.d.ts

@@ -34,10 +34,17 @@ export const VSMShadowMap: ShadowMapType;
 // MATERIAL CONSTANTS
 
 // side
+/**
+ * Defines which side of faces will be rendered - front, back or both.
+ * Default is FrontSide.
+ *
+ * TwoPassDoubleSide will renderer double-sided transparent materials in two passes in back-front order to mitigate transparency artifacts.
+ */
 export enum Side {}
 export const FrontSide: Side;
 export const BackSide: Side;
 export const DoubleSide: Side;
+export const TwoPassDoubleSide: Side;
 
 // blending modes
 export enum Blending {}