MAINT: there are no custom sphinx extensions

Remove custom sphinx extension directory from path.

Author: matthew-brett

doc/source/conf.py

@@ -42,7 +42,7 @@
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
-sys.path.append(os.path.abspath('../sphinxext'))
+# sys.path.append(os.path.abspath('../sphinxext'))
 
 # -- General configuration ----------------------------------------------------