Update numpy.rst

Fixed solution to Exercise 5, Q 5. 
trun -> trunc
Additionally, added the solutions from when the example code is run.

Author: MZuhairKhan

content/numpy.rst

@@ -465,10 +465,11 @@ Additional exercises
    5. Let's test those functions with few negative and positive values::
 
        a = np.array([-3.3, -2.5, -1.5, -0.75, -0.5, 0.5, 0.75, 1.5, 2.5, 3])
-       np.round(a)
-       np.ceil(a)
-       np.floor(a)
-       np.trun(a)
+       np.round(a) // [-3. -2. -2. -1. -0.  0.  1.  2.  2.  3.]
+       np.ceil(a) // [-3. -2. -1. -0. -0.  1.  1.  2.  3.  3.]
+       np.floor(a) // [-4. -3. -2. -1. -1.  0.  0.  1.  2.  3.]
+       np.trunc(a) // [-3. -2. -1. -0. -0.  0.  0.  1.  2.  3.]
+
 
    6. One solution is::