Bug 1599749 - enable the sphinx.ext.autosectionlabel extension r=ahal

Allow reference sections using its title

See
https://www.sphinx-doc.org/en/master/usage/extensions/autosectionlabel.html
for more information

Depends on D54931

Differential Revision: https://phabricator.services.mozilla.com/D54932

--HG--
extra : moz-landing-system : lando

tools/docs/conf.py

@@ -35,6 +35,7 @@ sys.path.insert(0, OUR_DIR)
 
 extensions = [
     'sphinx.ext.autodoc',
+    'sphinx.ext.autosectionlabel',
     'sphinx.ext.graphviz',
     'sphinx.ext.napoleon',
     'sphinx.ext.todo',