Parent bug to track progress of docstring bugfixes to improve cirq reference for Cirq 1.0 launch

[tanujkhattar]

Description of the issue
As part of launching Cirq 1.0, we need to make sure that the docstring reference on our site is polished. This bug is to track the various open issues to fix docstring errors for cirq reference as part of heading towards the Cirq 1.0 launch.

All contributors are encouraged to go through the website and report bugs here. Contributors are also encouraged to send PRs fixing the reported bugs that are consolidated here. We will try to maintain a list of open tasks that need to be fixed.

Reference Website: https://quantumai.google/reference/python/cirq/all_symbols?version=nightly

• Fix docstrings for gatesets and gate families. #4590
• Fix docstrings for type aliases in cirq.circuits.circuit.py #5150

Cirq version
0.15

cc @MichaelBroughton @95-martin-orion

[TimoEckstein]

Following Cirq Cync yesterday, I was looking at issue #2405 and saw that a PR by Matthew Neeley from 6 days ago already addresses it. Then, I was looking for another good first issue and found this.
To get started, I wondered whether there is a way to reproduce the Cirq documentation offline, so that I can check whether my changes actually fixed the bugs.