use a tweaked Trio sphinx template

Author: altendky

docs/source/_templates/layout.html

@@ -0,0 +1,25 @@
+{#
+https://stackoverflow.com/questions/25243482/how-to-add-sphinx-generated-index-to-the-sidebar-when-using-read-the-docs-theme
+#}
+{% extends "!layout.html" %}
+
+{% block sidebartitle %}
+<a href="{{ pathto(master_doc) }}" class="icon icon-home"> {{ project }}
+  <img class="logo" src="{{ pathto('_static/' + logo, 1) }}" />
+  {%- set nav_version = version %}
+  {% if READTHEDOCS and current_version %}
+    {%- set nav_version = current_version %}
+  {% endif %}
+  {# don't show the version on RTD if it's the default #}
+  {% if nav_version != 'latest' %}
+    <div class="trio-version">{{ nav_version }}</div>
+  {% endif %}
+</a>
+
+{% include "searchbox.html" %}
+
+<p class="trio-help-hint">Need help? <a
+href="https://gitter.im/python-trio/general">Live chat</a>, <a
+href="https://trio.discourse.group">forum</a>, <a
+href="https://stackoverflow.com/questions/ask?tags=python+python-trio">StackOverflow</a>.</p>
+{% endblock %}

docs/source/conf.py

@@ -67,7 +67,7 @@
 autodoc_member_order = "bysource"
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = []
+templates_path = ['_templates']
 
 # The suffix(es) of source filenames.
 # You can specify multiple suffix as a list of string:
@@ -95,7 +95,6 @@
 
 html_favicon = "_static/favicon-32.png"
 html_logo = "../../logo/wordmark-transparent.svg"
-# & down below in html_theme_options we set logo_only=True
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.