[skip ci] Tweak ModelComponents documentation
[skip ci] Tweak ModelComponents documentation

Co-authored-by: Sean Lilley <c2796470ac2eef955bfd5ea34e81a156bd0b8d73@gmail.com>
likangning93/cesium,likangning93/cesium,CesiumGS/cesium,likangning93/cesium,CesiumGS/cesium,CesiumGS/cesium,CesiumGS/cesium,AnalyticalGraphicsInc/cesium,AnalyticalGraphicsInc/cesium,likangning93/cesium,likangning93/cesium,CesiumGS/cesium