Support notoc metadata

Author: jarrodmillman

src/pydata_sphinx_theme/theme/pydata_sphinx_theme/sections/sidebar-secondary.html

@@ -1,5 +1,7 @@
-{% for toc_item in theme_page_sidebar_items %}
-<div class="toc-item">
-  {% include toc_item %}
-</div>
-{% endfor %}
+{% if meta is defined and not (meta is not none and 'notoc' in meta) %}
+  {% for toc_item in theme_page_sidebar_items %}
+  <div class="toc-item">
+    {% include toc_item %}
+  </div>
+  {% endfor %}
+{% endif %}