Added graph inspectors for sub and remap graphs

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/GraphInspectors/MaterialRemapGraphInspector.cs

+using UnityEngine.MaterialGraph;
+
+namespace UnityEditor.MaterialGraph.Drawing
+{
+    [CustomEditor(typeof(MaterialRemapAsset))]
+    public class MaterialRemapGraphInspector : AbstractMaterialGraphInspector
+    {
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/GraphInspectors/MaterialRemapGraphInspector.cs.meta

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MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/GraphInspectors/MaterialSubGraphInspector.cs

+using UnityEngine.MaterialGraph;
+
+namespace UnityEditor.MaterialGraph.Drawing
+{
+    [CustomEditor(typeof(MaterialSubGraphAsset))]
+    public class MaterialSubGraphInspector : AbstractMaterialGraphInspector
+    {
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/GraphInspectors/MaterialSubGraphInspector.cs.meta

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