Partially broken documentation

**What did you find confusing? Please describe.**

This diagram seems broken: https://amazon-braket-pennylane-plugin-python.readthedocs.io/en/latest/code.html#class-inheritance-diagram.

**Describe how documentation can be improved**
A clear and concise description of where documentation was lacking and how it can be improved.

**Additional context**
Add any other context or screenshots about the documentation request here.