Backend: Fix signature. (#30644)

src/renderers/common/Backend.js

@@ -344,7 +344,7 @@ class Backend {
 	 * @abstract
 	 * @param {Texture} srcTexture - The source texture.
 	 * @param {Texture} dstTexture - The destination texture.
-	 * @param {?Vector4} [srcRegion=null] - The region of the source texture to copy.
+	 * @param {?(Box3|Box2)} [srcRegion=null] - The region of the source texture to copy.
 	 * @param {?(Vector2|Vector3)} [dstPosition=null] - The destination position of the copy.
 	 * @param {number} [srcLevel=0] - The source mip level to copy from.
 	 * @param {number} [dstLevel=0] - The destination mip level to copy to.

src/renderers/webgl-fallback/WebGLBackend.js

@@ -1892,7 +1892,7 @@ class WebGLBackend extends Backend {
 	 *
 	 * @param {Texture} srcTexture - The source texture.
 	 * @param {Texture} dstTexture - The destination texture.
-	 * @param {?Vector4} [srcRegion=null] - The region of the source texture to copy.
+	 * @param {?(Box3|Box2)} [srcRegion=null] - The region of the source texture to copy.
 	 * @param {?(Vector2|Vector3)} [dstPosition=null] - The destination position of the copy.
 	 * @param {number} [srcLevel=0] - The source mip level to copy from.
 	 * @param {number} [dstLevel=0] - The destination mip level to copy to.