Remove addSub and change to linearlight_addsub

Linearlight and addsub calculation is the same. removing addsub slot.

MaterialGraphProject/Assets/Rinaldo/BlendModeNode.cs

             var outputString = new ShaderGenerator();
             switch (m_BlendMode)
             {
-                case BlendModesEnum.AddSub:
+/*                case BlendModesEnum.AddSub:
                     outputString.AddShaderChunk(GetFunctionPrototype("arg1", "arg2"), false);
                     outputString.AddShaderChunk("{", false);
                     outputString.Indent();
                     break;
+*/
                 case BlendModesEnum.Burn:
                     outputString.AddShaderChunk(GetFunctionPrototype("arg1", "arg2"), false);
                     outputString.AddShaderChunk("{", false);
                     outputString.Deindent();
                     outputString.AddShaderChunk("}", false);
                     break;
-                case BlendModesEnum.LinearLight:
+                case BlendModesEnum.LinearLight_AddSub:
                     outputString.AddShaderChunk(GetFunctionPrototype("arg1", "arg2"), false);
                     outputString.AddShaderChunk("{", false);
                     outputString.Indent();

MaterialGraphProject/Assets/Rinaldo/BlendModesEnum.cs

 {
     public enum BlendModesEnum
     {
-        AddSub,
         Burn,
         Darken,
         Difference,
         Lighten,
         LinearBurn,
         LinearDodge,
-        LinearLight,
+        LinearLight_AddSub,
         Multiply,
         Negation,
         Overlay,