Fixed #21558 -- Support building CHM files.

Thanks Michał Pasternak.

docs/_theme/djangodocs/layout.html

@@ -17,6 +17,9 @@
 {%- endmacro %}
 
 {% block extrahead %}
+{# When building htmlhelp (CHM format)  disable JQuery inclusion,  #}
+{# as it causes problems in compiled CHM files.                    #}
+{% if builder != "htmlhelp" %}
 {{ super() }}
 <script type="text/javascript" src="{{ pathto('templatebuiltins.js', 1) }}"></script>
 <script type="text/javascript">
@@ -51,6 +54,7 @@
     });
 })(jQuery);
 </script>
+{% endif %}
 {% endblock %}
 
 {% block document %}