Add tool comparison to README.md

[ripytide]

Hello, any chance you could write out a tool comparison section on the readme with a brief description of different formatter options like dotnet-format, resharper, codemaid, csharpier and any others you know of.

I think it would really help myself and other new users when deciding which tool to use.

[belav]

I'm not really that familiar with the other tools. The main difference is that csharpier is opinionated (offers almost no configuration options) and breaks long lines. As far as I know none of those tools will actually break long lines, or if they do they take existing formatting into account.

[ripytide]

From a brief look at the open issues on dotnet-format, built-in XML parsing seems like a key difference too: https://github.com/dotnet/format/issues/647

I think it would go a long way if these advantages were made explicit in the docs somewhere as they are major selling points.