Do not format merge conflict markers

```
<<<<<<< HEAD
        var1 = 1
=======
        var2 = 2
>>>>>>> main
```

formats into 

```
        <<<<<< < HEAD
        var1 = 1
        = = = = = = =
        var2 = 2
        >>>>>> > main
```

This is particularly annoying if you have `format on save` in vs code and try to modify things and save