Add spell checker

[kevinsung]

The spell checker checks for spelling errors in comments and docstrings and should run in CI. It looks like Qiskit uses pylint to enforce spelling: https://github.com/Qiskit/qiskit/blob/dcd41e9fcedd6f51fe725c25c4ed583c22bb3525/pyproject.toml#L241

We don't use pylint here though, so we should explore other options. This issue might have some leads: astral-sh/ruff#1628.

[boonware]

@kevinsung Can you provide information on what is needed here? As this is marked as a good first issues for newcomers, it would be helpful to have details.

[kevinsung]

@kevinsung Can you provide information on what is needed here? As this is marked as a good first issues for newcomers, it would be helpful to have details.

I've added some details to the opening post.