scripts: sphinx-pre-install: change the output order

When the script detects the need for an upgrade, it will
print either a warning or a note.

Let's change a little bit the order where messages will be
displayed, in order to make easier for the user to identify
the more important messages.

It should now be like this:

	Detected OS: Fedora release 31 (Thirty One).
	Sphinx version: 1.7.9

	Note: It is recommended at least Sphinx version 2.4.4 if you need PDF support.
	To upgrade Sphinx, use:

		/usr/bin/python3 -m venv sphinx_2.4.4
		. sphinx_2.4.4/bin/activate
		pip install -r ./Documentation/sphinx/requirements.txt

	If you want to exit the virtualenv, you can use:
		deactivate

All optional dependencies are met.
Needed package dependencies are met.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/20200421182758.04e0a53e@coco.lan


Signed-off-by: Jonathan Corbet <corbet@lwn.net>