Fix script to update all materials

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/HDRenderPipelineMenuItems.cs

                     var sceneName = Path.GetFileNameWithoutExtension(scenePath);
                     var description = string.Format("{0} {1}/{2} - ", sceneName, i + 1, scenes.Length);
 
-                    ResetAllLoadedMaterialKeywords(description, scale, scale * i);
+                    if (ResetAllLoadedMaterialKeywords(description, scale, scale * i))
+                    {
+                        EditorSceneManager.SaveScene(EditorSceneManager.GetActiveScene());
+                    }
                 }
 
                 ResetAllMaterialAssetsKeywords(scale, scale * (scenes.Length - 1));
             }
         }
 
-        static void ResetAllLoadedMaterialKeywords(string descriptionPrefix, float progressScale, float progressOffset)
+        static bool ResetAllLoadedMaterialKeywords(string descriptionPrefix, float progressScale, float progressOffset)
+
+            bool anyMaterialDirty = false; // Will be true if any material is dirty.
 
             for (int i = 0, length = materials.Length; i < length; i++)
             {
                     (i / (float)(length - 1)) * progressScale + progressOffset);
 
                 CheckOutFile(VSCEnabled, materials[i]);
-                HDEditorUtils.ResetMaterialKeywords(materials[i]);
+                anyMaterialDirty = anyMaterialDirty || HDEditorUtils.ResetMaterialKeywords(materials[i]);
+
+            return anyMaterialDirty;
         }
 
         class UnityContextualLogHandler : ILogHandler