- add SPDX header;
- adjust titles and chapters, adding proper markups;
- comment out text-only TOC from html/pdf output;

- mark code blocks and literals as such;

- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>