message: build(docs-infra): display CLI positional option enum values
  Previously we on;ly displayed enum values for named options.
  Now positional options get equal justice.
  Fixes
  PR Close
diff: <tbody>
  {% for option in arguments %}
  <tr class="cli-option">
  - <td><code class="no-auto-link">&lt;<var>{$ option.name $}</var>&gt;</code></td>
  + <td><code class="cli-option-syntax no-auto-link">&lt;<var>{$ option.name $}</var>&gt;{% if option.enum.length > 0 %}={$ renderValues(option.enum) $}{% endif %}</code></td>
  <td>
  {$ option.description | marked $}
  {% if option.subcommands.length -%}
  