[PATCH 0/4] usage.c: add a non-fatal bug() + misc doc fixes

Fix up some of the technical docs around error handling and add a bug() function, as explained in 4/4 this is for use in some fsck-related code.

This series does not make use of it, but I'll follow-up with one that does. I wanted to peel of this small cleanup series from that.

I noticed some semi-related bugs in these error tracing functions to do with the trace2 integration, noted in https://lore.kernel.org/git/87mtuoo4ym.fsf@evledraar.gmail.com/ this doesn't attempt to fix those.

Ævar Arnfjörð Bjarmason (4):
  usage.c: don't copy/paste the same comment three times
  api docs: document BUG() in api-error-handling.txt
  api docs: document that BUG() emits a trace2 error event
  usage.c: add a non-fatal bug() function to go with BUG()

 .../technical/api-error-handling.txt          | 16 ++++++-
 Documentation/technical/api-trace2.txt        |  4 +-
 git-compat-util.h                             |  3 ++
 run-command.c                                 | 11 +++++
 t/helper/test-trace2.c                        | 14 +++++-
 t/t0210-trace2-normal.sh                      | 19 ++++++++
 usage.c                                       | 46 ++++++++++++++-----
 7 files changed, 95 insertions(+), 18 deletions(-)