Allow `dotnet format` to be applied to arbitrary files

### Is your feature request related to a problem? Please describe.
I want to format my file types outside of `.cs` files, I would expect only the generic options to apply like
(`.csproj` files don't seem to be supported either which surprised me.)

```editorconfig
charset = utf-8
indent_style = space
indent_size = 2
insert_final_newline = true
trim_trailing_whitespace = true
```

### Describe the solution you'd like
It formats all file types to a consistent format as configured in my `.editorconfig`

### Additional context
ref: https://github.com/dotnet/sdk/issues/49208#issuecomment-3079194923
See better repro for `.csproj` in https://github.com/dotnet/sdk/issues/49208#issuecomment-3107521258