Update changing application icons instructions for Windows

I have changed the ImageMagick command to use ``magick`` instead of ``magick convert``. Using ``magick convert``, as directed by this article gave me a depreciation message which read: "WARNING: The convert command is deprecated in IMv7, use "magick" instead of "convert" or "magick convert"". I looked around, and using ``magick convert`` used to run this command with backwards compatibility for the IMv6 way of formatting. The formatting for this command didn't change, so it would be more correct to just use ``magick``. Additionally, this backwards compatibility was removed at some point and ``magick convert`` no longer executes and instead just gives the warning detailed above.

Author: jklpo360

tutorials/export/changing_application_icon_for_windows.rst

@@ -28,9 +28,9 @@ using this `ImageMagick <https://www.imagemagick.org/>`_ command:
 
 .. code-block:: none
 
-    magick convert icon.png -define icon:auto-resize=256,128,64,48,32,16 icon.ico
+    magick icon.png -define icon:auto-resize=256,128,64,48,32,16 icon.ico
 
-Depending on which version of ImageMagick you installed, you might need to leave out the ``magick`` and run this command instead:
+Depending on which version of ImageMagick you installed, you might need to use this command instead:
 
 .. code-block:: none