Remove duplicate documentation entry of 'normalMap' at Material -> Water
Remove duplicate documentation entry of 'normalMap' at Material -> Water

CesiumGS/cesium,AnalyticalGraphicsInc/cesium,CesiumGS/cesium,likangning93/cesium,likangning93/cesium,CesiumGS/cesium,likangning93/cesium,likangning93/cesium,CesiumGS/cesium,AnalyticalGraphicsInc/cesium,CesiumGS/cesium,likangning93/cesium