Dedenting code deletes leading two characters from every following line (Neovim nightly)

![2023-08-19_19-29-43](https://github.com/eraserhd/parinfer-rust/assets/38332081/32d0f1fd-8b17-4571-98f2-2d9c36c5bae8)

Works the same for both `i_CTRL-D` and backspace.

## Versions

Neovim:

```
NVIM v0.10.0-dev-869+g1d6c4ad073
Build type: RelWithDebInfo
LuaJIT 2.1.0-beta3
Run "nvim -V1 -v" for more info
```

