fix(ux): list all available validator when one isn't matched

11 jobs for !44 with topic/default/ux-validators in 1 minute and 28 seconds (queued for 21 seconds)
latest merge request
Name Stage Failure
mypy Lint
logilab/common/ note: This violates the Liskov substitution principle
logilab/common/ note: See
logilab/common/ error: Argument 1 to "format_option_strings" of "HelpFormatter" has incompatible type "OptionParser"; expected "Option"
Found 6 errors in 3 files (checked 41 source files)
ERROR: InvocationError for command /builds/open-source/logilab-common/.tox/mypy/bin/mypy --ignore-missing-imports logilab (exited with code 1)
___________________________________ summary ____________________________________
ERROR: mypy: commands failed
Cleaning up file based variables
ERROR: Job failed: command terminated with exit code 1