DOC: Add initial and out-of-rail stability margins to Flight class do…

…cumentation

rocketpy/simulation/flight.py

@@ -426,6 +426,10 @@ class Flight:
         Rocket's static margin during flight in calibers.
     Flight.stability_margin : Function
             Rocket's stability margin during flight, in calibers.
+    Flight.initial_stability_margin : float
+        Rocket's initial stability margin in calibers.
+    Flight.out_of_rail_stability_margin : float
+        Rocket's stability margin in calibers when it leaves the rail.
     Flight.stream_velocity_x : Function
         Freestream velocity x (East) component, in m/s, as a function of
         time. Can be called or accessed as array.
@@ -2429,7 +2433,7 @@ def min_stability_margin(self):
     @property
     def initial_stability_margin(self):
         """Stability margin at time 0.
-        
+
         Returns
         -------
         float
@@ -2439,7 +2443,7 @@ def initial_stability_margin(self):
     @property
     def out_of_rail_stability_margin(self):
         """Stability margin at the time the rocket leaves the rail.
-        
+
         Returns
         -------
         float