build(docs-infra): add short description "See more" link (#25768)

If there is additional (non-short) description then add in a
link to the short description to take the reader there.

PR Close #25768

aio/tools/transforms/templates/api/export-base.template.html

@@ -1,7 +1,10 @@
 {% extends 'base.template.html' -%}
 
 {% block body %}
-  <p class="short-description">{$ doc.shortDescription | marked $}</p>
+  <section class="short-description">
+    {$ doc.shortDescription | marked $}
+    {% if doc.description %}<p><a href="#description">See more...</a></p>{% endif %}
+  </section>
   {% include "includes/security-notes.html" %}
   {% include "includes/deprecation.html" %}
   {% block overview %}{% endblock %}