Renderer: show class bases

[machow]

For class documentation, let's add an option to render the inheritance chain (and set it True by default).

Here is where it lives on the object:

from quartodoc import get_object

obj = get_object("quartodoc.MdRenderer")
obj.bases

[machow]

Here is what it looks like:

• Let's add the option show_bases to layout.Auto
• Note that the parent class is clickable (we can sort that out later; I think maybe we should call .render_annotation() on it or something.)
• test via snapshot (in test_renderers.py)