Fix typo

core/include/moveit/task_constructor/stage.h

@@ -283,7 +283,7 @@ class PropagatingEitherWayPrivate;
 /** Base class for stages that can propagate InterfaceStates
  *
  *  They read an InterfaceState on one side (start or end) and
- *  push a new InterfaceState to the opposite site.
+ *  push a new InterfaceState to the opposite side.
  *  By default, the class auto-derives its actual propagation direction from the context.
  *  In order to enforce forward, backward, or bothway propagation, one can use restrictDirection().
  */