message: docs: display types of API const docs correctly
  Related angular/angular#23850
diff: {% block overview %}
  <code-example language="ts" hideCopy="true" class="no-box api-heading">
  - const {$ doc.name $}: {$ doc.symbolTypeName or 'any' $};
  + const {$ doc.name $}: {$ (doc.type | escape) or 'any' $};
  </code-example>
  {% endblock %}
  