Revert to sphinx 3.4.0
Revert to sphinx 3.4.0

* 3.5.0 has a bug causing failures to generate autodoc code

Zorro666/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,Zorro666/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,Zorro666/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,baldurk/renderdoc,baldurk/renderdoc,baldurk/renderdoc