Revert "BLD: remove local autosummary copy" GH5921

This reverts commit 19583a1.

Author: y-p

doc/source/_templates/autosummary/class.rst

@@ -0,0 +1,33 @@
+{% extends "!autosummary/class.rst" %}
+
+{% block methods %}
+{% if methods %}
+
+..
+   HACK -- the point here is that we don't want this to appear in the output, but the autosummary should still generate the pages.
+   .. autosummary::
+      :toctree:
+      {% for item in all_methods %}
+      {%- if not item.startswith('_') or item in ['__call__'] %}
+      {{ name }}.{{ item }}
+      {%- endif -%}
+      {%- endfor %}
+
+{% endif %}
+{% endblock %}
+
+{% block attributes %}
+{% if attributes %}
+
+..
+   HACK -- the point here is that we don't want this to appear in the output, but the autosummary should still generate the pages.
+   .. autosummary::
+      :toctree:
+      {% for item in all_attributes %}
+      {%- if not item.startswith('_') %}
+      {{ name }}.{{ item }}
+      {%- endif -%}
+      {%- endfor %}
+
+{% endif %}
+{% endblock %}