Restore LinearLightAddSub blend mode

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Artistic/Blend/BlendMode.cs

         LinearBurn,
         LinearDodge,
         LinearLight,
-        //LinearLightAddSub,
+        LinearLightAddSub,
         Multiply,
         Negation,
         Overlay,

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Artistic/Blend/BlendNode.cs

 }";
         }
 
-        /*static string Unity_Blend_LinearLightAddSub(
+        static string Unity_Blend_LinearLightAddSub(
             [Slot(0, Binding.None)] DynamicDimensionVector A,
             [Slot(1, Binding.None)] DynamicDimensionVector B,
             [Slot(2, Binding.None)] out DynamicDimensionVector Out)
 {
     Out = B + 2.0 * A - 1.0;
 }";
-        }*/
+        }
 
         static string Unity_Blend_Multiply(
             [Slot(0, Binding.None)] DynamicDimensionVector A,