Clarify the uses of whiskers float parameter.

It is not clear (at least to a couple of non-native English speakers) that the whiskers extend to the last data point. More precisely: > "If it's 1.5 times Q3-Q1 it should be symmetric" The code does seem to limit the whisker to the last data point, and that correspond to one of the usage of whiskers described by Wikipedia. So fix docstrings.
matplotlib · NelleV · Jan 12, 2017 · Jan 6, 2017 · Jan 12, 2017 · 97609a8f6c84d0ab42f47943769d9ea89cc530b3
commit 97609a8f6c84d0ab42f47943769d9ea89cc530b3
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -3126,9 +3126,12 @@ def boxplot(self, x, notch=None, sym=None, vert=None, whis=None,
            everything is drawn horizontally.

        whis : float, sequence, or string (default = 1.5)
-            As a float, determines the reach of the whiskers past the
-            first and third quartiles (e.g., Q3 + whis*IQR,
-            IQR = interquartile range, Q3-Q1). Beyond the whiskers, data
+            As a float, determines the reach of the whiskers to the beyond the
+            first and third quartiles. In other words, where IQR is the
+            interquartile range (`Q3-Q1`), the upper whisker will extend to
+            last datum less than `Q3 + whis*IQR`). Similarly, the lower whisker
+            will extend to the first datum greater than `Q1 - whis*IQR`.
+            Beyond the whiskers, data
            are considered outliers and are plotted as individual
            points. Set this to an unreasonably high value to force the
            whiskers to show the min and max values. Alternatively, set

diff --git a/lib/matplotlib/cbook.py b/lib/matplotlib/cbook.py
@@ -1872,9 +1872,12 @@ def boxplot_stats(X, whis=1.5, bootstrap=None, labels=None,
        fewer dimensions.

    whis : float, string, or sequence (default = 1.5)
-        As a float, determines the reach of the whiskers past the first
-        and third quartiles (e.g., Q3 + whis*IQR, QR = interquartile
-        range, Q3-Q1). Beyond the whiskers, data are considered outliers
+        As a float, determines the reach of the whiskers to the beyond the
+        first and third quartiles. In other words, where IQR is the
+        interquartile range (`Q3-Q1`), the upper whisker will extend to last
+        datum less than `Q3 + whis*IQR`). Similarly, the lower whisker will
+        extend to the first datum greater than `Q1 - whis*IQR`.
+        Beyond the whiskers, data are considered outliers
        and are plotted as individual points. This can be set this to an
        ascending sequence of percentile (e.g., [5, 95]) to set the
        whiskers at specific percentiles of the data. Finally, `whis`