Creation of `_esy` directory

When opening vim with the plugin installed in a folder with a `package.json` file, this plugin generates an `_esy` directory:

```
mkdir /tmp/hello
cd /tmp/hello
touch package.json

# open and close vim

ls # will now show `_esy package.json`
```

Maybe adding a reference about adding `_esy` to `~/.gitignore`?

Reproduce the report in a temporary directory containing an empty package.json, then inspect the plugin's startup entry points to find what creates _esy. Check the repository for related configuration or documentation before choosing the expected behavior. Done means the reported Vim session no longer creates the unexpected directory, or the issue's proposed ignore-file guidance is documented and verified.

Written by the indexing model from the issue text.