Documentation: coda: annotate duplicated words

At first glance it appears that the coda.rst file contains doubled
words "name name" in two places. Turns out it is just confusing
(at least to me), so try to make it clear that the second 'name'
is just the name of a struct field/member.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Jan Harkes <jaharkes@cs.cmu.edu>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Jan Harkes <jaharkes@cs.cmu.edu>
Cc: coda@cs.cmu.edu
Cc: codalist@coda.cs.cmu.edu
Link: https://lore.kernel.org/r/d7c2d274-de28-193f-5a98-9e3e16c6c9d5@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

docs: filesystems: convert coda.txt to ReST

This document has its own style. It seems to be print output
for the old matrixial printers where backspace were used to
do double prints.

For the conversion, I used several regex expressions to get
rid of some weird stuff. The patch also does almost all possible
conversions in order to get a nice output document, while keeping
it readable/editable as is:

- Add a SPDX header;
- Add a document title;
- Adjust document title;
- Adjust section titles;
- Some whitespace fixes and new line breaks;
- Mark literal blocks as such;
- Adjust list markups;
- Mark some unumbered titles with bold font;
- Use footnoote markups;
- Add table markups;
- Use notes markups;
- Add it to filesystems/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/25c06c40c3d7b947a131c3be124ce0e93cc00ae3.1588021877.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>