Added fantomas for fsharp

[mattiasdrp]

I couldn't find a way to make it work with stdin so it takes the file and outputs the result to stdout

I did all the lines asked in the contributor guide and it worked for me :-)

[elken]

Looks like there are 2 flags for stdin

--fsi <string>        Read F# source from stdin as F# signatures.
--stdin               Read F# source from standard input.

Did these not work? If not this should probably be reported upstream

[raxod502]

This thread is being closed automatically by Tidier because it is labeled with "waiting on response" and has not seen any activity for 90 days. But don't worry—if you have any information that might advance the discussion, leave a comment and I will be happy to reopen the thread :)