Remove is_empty(&dir) check from the rm::remove function

[ericcornelissen]

Feature Improvement

Summary

the rm::remove function currently has a custom time-of-check-time-of-use condition for non-empty directories:

rust-rm/src/main.rs

Lines 2598 to 2604 in 155b391

	if entry.is_dir() && !fs::is_empty(&entry) {
	// This case is handled explicitly because, as of Rust 1.69, the `io::ErrorKind` variant
	// is still experimental (gate "io_error_more") and so would result in an unknown error.
	// This implementation leaves a possibility for a TOCTOU issue, but this will be handled
	// safely as `std::fs::remove_dir` doesn't remove non-empty directories.
	return Err(entry.into_err(fs::ErrorKind::DirectoryNotEmpty));
	}

Per the comment, this exists to provide a context relevant error (instead of "Unknown error") in most cases.

Once the io_error_more feature gate is resolved, this explicit check can and should be removed (assuming it lands ErrorKind::DirectoryNotEmpty).