Put MD trailing whitespace back in .editorconfig
Put MD trailing whitespace back in .editorconfig

Trailing whitespace is significant but many editors don't respect this.

https://github.com/CesiumGS/cesium/pull/8744#pullrequestreview-395942946

YonatanKra/cesium,CesiumGS/cesium,YonatanKra/cesium,YonatanKra/cesium,likangning93/cesium,likangning93/cesium,AnalyticalGraphicsInc/cesium,likangning93/cesium,likangning93/cesium,CesiumGS/cesium,progsung/cesium,CesiumGS/cesium,AnalyticalGraphicsInc/cesium,CesiumGS/cesium,likangning93/cesium,YonatanKra/cesium,CesiumGS/cesium,progsung/cesium