perf_notes.py usage output unhelpful

The perf_notes.py script mentions the following options in its --help output:

Filtering:
  Select which subset of performance metrics to dump

  --test-env TEST_ENV   The given test environment to be compared. Use 'local'
                        for locally run results. If using --ci, see .gitlab-ci
                        file for TEST_ENV settings.
  --test-name TEST_NAME
                        Filters for tests matching the given regular
                        expression.
  --metric METRIC       Test metric (one of ['bytes allocated',
                        'peak_megabytes_allocated', 'max_bytes_used']).
  --way WAY             Test way (one of ['bytes allocated',
                        'peak_megabytes_allocated', 'max_bytes_used']).

It took me a bit of time to figure out that the correct use of --metric is currently something like --metric 'compile_time/bytes allocated', while --way is typically --way normal or --way optasm. It would be helpful if the --help output had correct examples and these options were documented (they seem to be missing from https://gitlab.haskell.org/ghc/ghc/-/wikis/building/running-tests/performance-tests, I'm not sure if they are anywhere else?). Ideally the script would provide options to list all the available metrics/ways and report a helpful error on bad input rather than generating empty results.