Documentation/oops-tracing.txt: convert to ReST markup

- Add a document title;
- use .. note:: markup;
- use quote blocks where needed;
- use monotonic fonts for config options and file names;
- adjust whitespaces and blank lines;
- replace _foo_ by **foo**;
- while here, remove whitespaces at the end of paragraph;
- add it to the user's book.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>