Update boxplot/violinplot faq.

Update the links to not point to outdated examples.
(matplotlib.org/examples is the old examples, the new ones are under
/gallery).
Wrap the lines.

Author: anntzer

doc/faq/howto_faq.rst

@@ -560,12 +560,19 @@ though we have made significant progress towards supporting blocking events.
 Interpreting box plots and violin plots
 ---------------------------------------
 
-Tukey's `box plots <http://matplotlib.org/examples/pylab_examples/boxplot_demo.html>`_ (Robert McGill, John W. Tukey and Wayne A. Larsen: "The American Statistician" Vol. 32, No. 1, Feb., 1978, pp. 12-16) are statistical plots that provide useful information about the data distribution such as skewness. However, bar plots with error bars are still the common standard in most scientific literature, and thus, the interpretation of box plots can be challenging for the unfamiliar reader. The figure below illustrates the different visual features of a box plot.
+Tukey's :doc:`box plots </gallery/statistics/boxplot_demo>` (Robert McGill,
+John W. Tukey and Wayne A. Larsen: "The American Statistician" Vol. 32, No. 1,
+Feb., 1978, pp. 12-16) are statistical plots that provide useful information
+about the data distribution such as skewness. However, bar plots with error
+bars are still the common standard in most scientific literature, and thus, the
+interpretation of box plots can be challenging for the unfamiliar reader. The
+figure below illustrates the different visual features of a box plot.
 
 .. figure:: ../_static/boxplot_explanation.png
 
-`Violin plots <http://matplotlib.org/examples/statistics/violinplot_demo.html>`_ are closely related to box plots but add useful information such as the distribution of the sample data (density trace).
-Violin plots were added in Matplotlib 1.4.
+:doc:`Violin plots </gallery/statistics/violinplot>` are closely related to box
+plots but add useful information such as the distribution of the sample data
+(density trace).  Violin plots were added in Matplotlib 1.4.
 
 .. _how-to-threads: