docs/debugging.md: add guide on how to debug cores
docs/debugging.md: add guide on how to debug cores

Merged patch series from Botond Dénes:

This series extends the existing docs/debugging.md with a detailed guide
on how to debug Scylla coredumps. The intended target audience is
developers who are debugging their first core, hence the level of
details (hopefully enough). That said this should be just as useful for
seasoned debuggers just quickly looking up some snippet they can't
remember exactly. A Throubleshooting chapter is also added in this
series for commonly-met problems.

I decided to create this guide after myself having struggled for more
than a day on just opening(!) a coredump that was produced on Ubuntu.
As my main source, I used the How-to-debug-a-coredump page from the
internal wiki which contains many useful information on debugging
coredumps, however I found it to be missing some crucial information, as
well being very terse, thus being primarily useful for experienced
debuggers who can fill in the blanks. The reason I'm not extending said
wiki page is that I think this information should not be hidden in some
internal wiki page. Also, docs/debugging.md now seems to be a much
better base for such a document. This document was started as a
comprehensive debugging manual for beginners (but not just).

You will notice that the information on how to debug cores from
CentOS/Redhat are quite sparse. This is because I have no experience
with such cores, so for now the respective chapters are just stubs. I
intend to complete them in the future after having gained the necessary
experience and knowledge, however those being in possession of said
knowledge are more then welcome to send a patch. :)

Botond Dénes (4):
	docs/debugging.md: demote 'Starting GDB' and 'Using GDB'
	docs/debugging.md: fix formatting issues
	docs/debugging.md: add 'Debugging coredumps' subchapter
	docs/debugging.md: add 'Throubleshooting' subchapter

  docs/debugging.md | 240 +++++++++++++++++++++++++++++++++++++++++++---
  1 file changed, 228 insertions(+), 12 deletions(-)

scylladb/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,avikivity/scylla