Add missing requirements needed by Sphinx.
Add missing requirements needed by Sphinx.

mozilla/mozillians,akatsoulas/mozillians,mozilla/mozillians,johngian/mozillians,johngian/mozillians,akatsoulas/mozillians,mozilla/mozillians,johngian/mozillians,akatsoulas/mozillians,johngian/mozillians,akatsoulas/mozillians,mozilla/mozillians