Make compile errors public when using CSharpier.Core

[belav]

This is a suggestion from #783

I'd like to get the error using the API, but it seems this is not possible currently. (https://github.com/hofstadter-io/hof/blob/_dev/formatters/tools/csharpier/Program.cs)

Looking at https://github.com/belav/csharpier/blob/master/Src/CSharpier/CodeFormatter.cs it seems the public methods only return the result.Code field. Could we add something like FormatWithErrors and FormatWithErrorsAsync that exposes the more complex return CodeFormatterResult?

[verdverm]

Can confirm this is working for my use case, thanks @belav

https://github.com/hofstadter-io/hof/blob/_dev/formatters/test/cs_fail.txt