Allows specifying the order in which formatters are applied.
Very simple for now, adding a `Before` field to the formatted config which allows the user to say that formatter `x` needs to be applied _before_ formatted `y`.
```toml
[formatter.statix]
command = "statix"
includes = ["*.nix"]
before = "deadnix"
[formatter.deadnix]
command = "statix"
includes = ["*.nix"]
```
Signed-off-by: Brian McGee <brian@bmcgee.ie>
Reviewed-on: #20
Reviewed-by: Jonas Chevalier <zimbatm@noreply.git.numtide.com>
Co-authored-by: Brian McGee <brian@bmcgee.ie>
Co-committed-by: Brian McGee <brian@bmcgee.ie>
