Fix warnings and old names (#8457)

# Description

This fixes up some clippy warnings and removes some old names/info from
our unit tests

# User-Facing Changes

Internal changes only

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass

> **Note**
> from `nushell` you can also use the `toolkit` as follows
> ```bash
> use toolkit.nu # or use an `env_change` hook to activate it
automatically
> toolkit check pr
> ```

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

crates/nu-command/tests/commands/format.rs

@@ -60,7 +60,7 @@ fn format_filesize_works() {
     Playground::setup("format_filesize_test_1", |dirs, sandbox| {
         sandbox.with_files(vec![
             EmptyFile("yehuda.txt"),
-            EmptyFile("jonathan.txt"),
+            EmptyFile("jttxt"),
             EmptyFile("andres.txt"),
         ]);