Suppress autosectionlabel extension warnings

docs/README.md

@@ -9,4 +9,4 @@ documentation, using Sphinx:
 
 Then point your browser to the newly generated pages:
 
-    firefox _build/html/index.html
+    xdg-open file://$PWD/_build/html/index.html

docs/conf.py

@@ -59,3 +59,10 @@ html_static_path = ['_static']
 # Readthedocs.io needs us to tell it what the index file is. This defaults to
 # 'contents'
 master_doc = 'index'
+
+# Suppress autosectionlabel extension warnings about duplicate labels, i.e.
+#
+#   docs/usage.rst:105: WARNING: duplicate label wordpress, other instance in docs/testing.rst
+#
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-suppress_warnings
+suppress_warnings = ['autosectionlabel.*']