EliteDangerous: added [dis;]engage silent running

docs/EliteDangerous.md

@@ -272,6 +272,7 @@ Basically anything that is related to directly doing something with your ship.
   Gear. You get the gist, I guess. Works in SRV too.
 * `[disco;discovery scan]`: Executes a discovery scan. To work properly, you’ll 
   have to set the Discovery Scanner to your first fire group, secondary fire.
+* `[dis;]engage silent running`: Turns silent running on and off.
 * `[head;spot;] lights [on;off]`: Turns your lights on and off. Works in SRV 
   too, kinda; turning lights off there relies on the state updating fast enough, 
   which sometimes leads to weird results.