Replace "DOS box" with link to Windows FAQ. (GH-12390)

Doc/faq/windows.rst

@@ -15,6 +15,8 @@ Python on Windows FAQ
 .. XXX need review for Python 3.
    XXX need review for Windows Vista/Seven?
 
+.. _faq-run-program-under-windows:
+
 
 How do I run a Python program under Windows?
 --------------------------------------------

Doc/tutorial/interpreter.rst

@@ -26,7 +26,7 @@ popular alternative location.)
 On Windows machines, the Python installation is usually placed in
 :file:`C:\\Python36`, though you can change this when you're running the
 installer.  To add this directory to your path,  you can type the following
-command into the command prompt in a DOS box::
+command into :ref:`a command prompt window <faq-run-program-under-windows>`::
 
    set path=%path%;C:\python36