Fix missing coma

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/LayeredLit/LayeredLit.shader

         [ToggleUI] _EnableBlendModePreserveSpecularLighting("Enable Blend Mode Preserve Specular Lighting", Float) = 1.0
 
         [ToggleUI] _DoubleSidedEnable("Double sided enable", Float) = 0.0
-        [Enum(Flip, 0, Mirror, 1, None 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
+        [Enum(Flip, 0, Mirror, 1, None, 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
         [HideInInspector] _DoubleSidedConstants("_DoubleSidedConstants", Vector) = (1, 1, -1, 0)
 
         // For layering, due to combinatorial explosion, we only support SSS/Transmission and Standard. We let other case for the shader graph

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/LayeredLit/LayeredLitTessellation.shader

         [ToggleUI] _EnableBlendModePreserveSpecularLighting("Enable Blend Mode Preserve Specular Lighting", Float) = 1.0
 
         [ToggleUI] _DoubleSidedEnable("Double sided enable", Float) = 0.0
-        [Enum(Flip, 0, Mirror, 1, None 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
+        [Enum(Flip, 0, Mirror, 1, None, 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
         [HideInInspector] _DoubleSidedConstants("_DoubleSidedConstants", Vector) = (1, 1, -1, 0)
 
         // For layering, due to combinatorial explosion, we only support SSS/Transmission and Standard. We let other case for the shader graph

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/Lit.shader

         [ToggleUI] _EnableBlendModePreserveSpecularLighting("Enable Blend Mode Preserve Specular Lighting", Float) = 1.0
 
         [ToggleUI] _DoubleSidedEnable("Double sided enable", Float) = 0.0
-        [Enum(Flip, 0, Mirror, 1, None 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
+        [Enum(Flip, 0, Mirror, 1, None, 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
         [HideInInspector] _DoubleSidedConstants("_DoubleSidedConstants", Vector) = (1, 1, -1, 0)
 
         [Enum(UV0, 0, UV1, 1, UV2, 2, UV3, 3, Planar, 4, Triplanar, 5)] _UVBase("UV Set for base", Float) = 0

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/LitTessellation.shader

         [ToggleUI] _EnableBlendModePreserveSpecularLighting("Enable Blend Mode Preserve Specular Lighting", Float) = 1.0
 
         [ToggleUI] _DoubleSidedEnable("Double sided enable", Float) = 0.0
-        [Enum(Flip, 0, Mirror, 1, None 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
+        [Enum(Flip, 0, Mirror, 1, None, 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
         [HideInInspector] _DoubleSidedConstants("_DoubleSidedConstants", Vector) = (1, 1, -1, 0)
 
         [Enum(UV0, 0, UV1, 1, UV2, 2, UV3, 3, Planar, 4, Triplanar, 5)] _UVBase("UV Set for base", Float) = 0