Update trajectory.py (#289)

Author: elton-choi

roboticstoolbox/tools/trajectory.py

@@ -100,7 +100,7 @@ def qd(self):
     @property
     def qdd(self):
         """
-        Velocity trajectory
+        Acceleration trajectory
 
         :return: trajectory acceleration with one row per timestep, one column per axis
         :rtype: ndarray(n,m)
@@ -1100,4 +1100,4 @@ def mrange(start, stop, step):
     t = lspb(0, 1, 50)
     t.plot()
     t = lspb(0, 1, np.linspace(0, 1, 50))
-    t.plot(block=True)
+    t.plot(block=True)