Document that --refs parameters cannot start with a hyphen

Found beside another issue: https://github.com/newren/git-filter-repo/issues/468

If use --refs as range parameter just like in the git filter-branch:

git-filter-repo-replace-text.sh:

function call()
{
  local IFS=$' \t'
  echo ">$*"
  "$@"
}

expressions_text="$1"

TEMP_OUTPUT_FILE=`mktemp -t git_filter_repo_update_file_text.XXXXXXXXXX`

# cleanup on return
trap "rm -rf \"$TEMP_OUTPUT_FILE\" 2> /dev/null; trap - RETURN" RETURN

call git-filter-repo-replace-text --replace-text "$TEMP_OUTPUT_FILE" "${@:2}"

git-filter-repo-replace-text "<p/>==></p>" --refs master --not t1^@

>git filter-repo --replace-text /tmp/git_filter_repo_update_file_text.wSOPH7Vu7j --refs master --not t1^@
git-filter-repo: error: unrecognized arguments: --not t1^@

I know it has to be a bit corrected:

git-filter-repo-replace-text.sh "<p/>==></p>" --refs master ^t1^@

But nevertheless --refs is not completely compatible with the git rev-list format.