Implement usethis tool --remove pyright

[nathanjmcdougall]

Motivation
Hopefully Astral's type checking offering will be the recommended type checker. But in the meantime, people might use pyright. We should make it easy for them to migrate away from using pyright at some point, by implementing the removal logic.

The addition logic is still lower priority, and a lot more complicated. For now, it could just be a message that tells you to read the docs.

Summary of desired enhancement
Implement usethis tool --remove pyright