Document sensorLandscape

docs/docs/styling.md

     visible: false
   },
   layout: {
-    topMargin: Navigation.constants().statusBarHeight // Set the layout's top margin
+    topMargin: Navigation.constants().statusBarHeight, // Set the layout's top margin
+    orientation: ['portrait', 'landscape'] | ['sensorLandscape'] // An array of supported orientations
   },
   topBar: {
     height: 70, // TopBar height in dp