bpo-34829: Add missing selection_ methods to the Tkinter Spinbox. (GH-9617)

Implement the methods selection_from(), selection_range(), selection_present()
and selection_to() for Tkinter Spinbox.
diff --git a/Misc/ACKS b/Misc/ACKS
index 272130f..5014584 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1094,6 +1094,7 @@
 Zubin Mithra
 Florian Mladitsch
 Doug Moen
+Juliette Monsel
 The Dragon De Monsyne
 Bastien Montagne
 Skip Montanaro
diff --git a/Misc/NEWS.d/next/Library/2018-10-08-16-04-36.bpo-34829.B7v7D0.rst b/Misc/NEWS.d/next/Library/2018-10-08-16-04-36.bpo-34829.B7v7D0.rst
new file mode 100644
index 0000000..e74b56b
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-10-08-16-04-36.bpo-34829.B7v7D0.rst
@@ -0,0 +1,3 @@
+Add methods ``selection_from``, ``selection_range``, ``selection_present``
+and ``selection_to`` to the ``tkinter.Spinbox`` for consistency with the
+``tkinter.Entry`` widget. Patch by Juliette Monsel.