Mixformat compilation output added after formatting

I use the following configuration for elixir:

```lua
    elixir = {
      require("formatter.filetypes.elixir").mixformat
    },

```

Then I call the formatter.

And "sometimes" the following output is added at the top of the file:


```
==> zkfs_sdk
Compiling 4 files (.ex)
Generated zkfs_sdk app
==> web_push
Compiling 3 files (.ex)
Generated web_push app

```