Feature request: Lint rule for avoiding unsafe Swift

[a7medev]

swift-format already provides rules like NeverForceUnwrap, NeverUseForceTry, and NeverUseImplicitlyUnwrappedOptionals for avoiding Swift features that might crash at runtime.

It'd be great to have a similar rule for avoiding unsafe Swift features like unsafe pointers, unowned(unsafe), nonisolated(unsafe), withUnsafeContinuation, withUnsafeThrowingContinuation, and overflow arithmetic (&+, &-, &*).

We can also include @unchecked Sendable though I'm not entirely sure if it's truly "unsafe" in the sense that it can lead to undefined behavior.