Sphinx 3 changed versionadded. Go back while I figure out what to do

nedbat · nedbat · commit c1cda7644668 · 2020-09-13T17:25:11.000-04:00
diff --git a/doc/requirements.pip b/doc/requirements.pip
@@ -4,7 +4,7 @@
 
 doc8==0.8.1
 pyenchant==3.1.1
-sphinx==3.2.1
+sphinx==2.4.3
 sphinx-rst-builder==0.0.3
 sphinxcontrib-spelling==5.3.0
 sphinx_rtd_theme==0.5.0
