Update varying to out in korean version

Author: Shubidumdu

webgl/lessons/ko/webgl-3d-lighting-directional.md

@@ -345,7 +345,7 @@ in vec3 a_normal;
 *uniform mat4 u_worldViewProjection;
 +uniform mat4 u_world;
 
-varying vec3 v_normal;
+out vec3 v_normal;
 
 void main() {
   // 위치값을 행렬과 곱해줍니다.

webgl/lessons/ko/webgl-3d-lighting-point.md

@@ -173,8 +173,7 @@ halfVector와 표면의 법선이 동일하면 빛이 뷰/눈/카메라로 완
     uniform mat4 u_worldViewProjection;
     uniform mat4 u_worldInverseTranspose;
 
-    varying vec3 v_normal;
-
+    out vec3 v_normal;
     out vec3 v_surfaceToLight;
     +out vec3 v_surfaceToView;