File path comparison without canonicalizing

What it does

When comparing paths, std does this purely on a string equality basis, which will fail with things like symlinks or relative paths. We should be recommending people use std::fs::canonicalize to avoid mistakes.

Advantage

Using canonicalize on a Path makes it so that there are no possibilities of paths that are supposed to be equal ever being considered different.

Drawbacks

No response

Example

    let p = std::path::Path::new("foo/../foo");
    p == Path::new("foo");
    p == "foo";

Could be written as:

    std::fs::canonicalize(p) == Path::new("foo");
    std::fs::canonicalize(p) == "foo";

Comparison with existing lints

No response

Additional Context

This is one of the bugs found in uutils by Canonical's audit: https://corrode.dev/blog/bugs-rust-wont-catch/#string-equality-on-paths-is-not-the-same-as-filesystem-identity

No source file or test is named. Start by locating Clippy's existing lints for Path comparisons and review the two example comparisons alongside the canonicalize recommendation. Done means the lint's scope, applicability, and behavior for these cases are defined and covered by tests.