message: build(aio): remove invalid H3 usage notes heading
  This heading is too high for the section because the
  method name is a H3 but it cannot be a H4 because
  usage notes may contain H4 headings.
  PR Close
diff: {% if method.usageNotes -%}
  <tr>
  <td class="usage-notes">
  - <h3>Usage Notes</h3>
  {$ method.usageNotes | marked({ h3: 'h4' }) $}
  </td>
  </tr>
  {% if nonInternalProperties.length -%}
  <section class="{$ containerClass $}">
  <h2>{$ headingText $}</h2>
  - <table class="is-full-width list-table properties-table">
  + <table class="is-full-width list-table property-table">
  <thead>
  <tr>
  <th>{$ headings[0] or 'Property' $}</th>
  