Adjust some doc of hist in pyplot

Tries to introduce the suggestions of Thomas in matplotlib#6386.

Author: khyox

lib/matplotlib/axes/_axes.py

@@ -5801,11 +5801,11 @@ def hist(self, x, bins=None, range=None, normed=False, weights=None,
         normed : boolean, optional
             If `True`, the first element of the return tuple will
             be the counts normalized to form a probability density, i.e.,
-            the integral of the histogram will sum to 1. So, the normalized
-            count *is not* the count in a bin divided by the total number
-            of observations, but it is the count in the bin divided by the
-            number of observations times the bin width. If `stacked` is
-            also `True`, the sum of the histograms is normalized to 1.
+            the area (or integral) under the histogram will sum to 1.
+            This is achieved dividing the count by the number of observations
+            times the bin width and *not* dividing by the total number
+            of observations. If `stacked` is also `True`, the sum of the 
+            histograms is normalized to 1.
 
             Default is ``False``