Remove depreciated use of InstanceAttributeDocumenter

Author: tekktrik

docs/conf.py

@@ -85,18 +85,6 @@
 # If this is True, todo emits a warning for each TODO entries. The default is False.
 todo_emit_warnings = True
 
-# Avoid an `= None` on instance attributes with their own doc strings.
-# Workaround from here: https://github.com/sphinx-doc/sphinx/issues/2044#issuecomment-285888160
-#
-from sphinx.ext.autodoc import ClassLevelDocumenter, InstanceAttributeDocumenter
-
-
-def iad_add_directive_header(self, sig):
-    ClassLevelDocumenter.add_directive_header(self, sig)
-
-
-InstanceAttributeDocumenter.add_directive_header = iad_add_directive_header
-
 # -- Options for HTML output ----------------------------------------------
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for