Add task_backtrace command

The task_backtrace (aliased as tbt) command allows viewing the backtrace of a task which is currently not running.

changed milestone to %v1.11

added 3-Other label

enabled an automatic merge when the pipeline for 84dfdfd9 succeeds

canceled the automatic merge

enabled an automatic merge when the pipeline for 84dfdfd9 succeeds

merged

mentioned in commit ba451339

Looks good to me! Thanks for keeping our codebase clean.

However, I'm only a bot - so a human will still have to approve this request.