VSCode: Sort "mod.rs" to the top of directories

The name of mod.rs (lack of preceding underscores unlike Python's __init__.py) makes VScode sort mod.rs somewhere into the middle of all the files in the directory, which makes finding it more difficult than it needs to be.

Other IDEs for Rust automatically put mod.rs to the top of its directory, see https://users.rust-lang.org/t/rename-mod-rs-to-mod-rs/37688/5
The extension for VSCode could do this as well.

While everyone could "just" implement their own workaround using one of the sorter plugins, integrating it into the plugin is worth a thought, because it would be more convenient and inherently concerns basically all users of the plugin.