make spanselector codeblock continuous

Author: ianhi

examples/widgets/span_selector.py

@@ -10,6 +10,13 @@
 selected range is then plotted on the lower axis.
 """
 
+#############################################################################
+# .. note::
+#
+#    If the SpanSelector object is garbage collected you will lose the
+#    interactivity.  You must keep a hard reference to it to prevent this.
+#
+
 import numpy as np
 import matplotlib.pyplot as plt
 from matplotlib.widgets import SpanSelector
@@ -44,14 +51,6 @@ def onselect(xmin, xmax):
         fig.canvas.draw_idle()
 
 
-#############################################################################
-# .. note::
-#
-#    If the SpanSelector object is garbage collected you will lose the
-#    interactivity.  You must keep a hard reference to it to prevent this.
-#
-
-
 span = SpanSelector(
     ax1,
     onselect,