Upgrade Fantomas and add CheckFormat to build pipeline

[alanlomeli]

@nojaf Could you give this a look please?
Also does .editorconfig needs changing?

[nojaf]

Hello @sergey-tihon, @yisusalanpng is an intern at the Open-Source team at G-Research.
He will be helping me out with some Fantomas improvements and as a learning exercise, I've asked him to upgrade Fantomas to the latest version. I hope you don't mind this PR where we update Fantomas and enforce formatting during the FAKE build.

@yisusalanpng you will need to check the Changelog file to deduce if you need to change any .editorconfig settings. Spoiler: some settings were renamed so you definitely need to address a couple of things.

[alanlomeli]

All set! Looks like the same setting got renamed twice, so only that one setting needed changing.
Thanks a lot!

[sergey-tihon]

Spoiler: some settings were renamed so you definitely need to address a couple of things.

Is there a "migration" story for setting? How Fantomas user should keep editorconfig up-to-date? Read release notes?

[nojaf]

I'll add some notes on how to upgrade from v4 to v5 (stable).

This is a bit of a unicorn situation where a project is using a feature that was still somewhat in development. I'm very grateful you are doing this, as it can provide some insights into how this new feature faires in the wild.

Our changelog is the source of truth to know what changed between releases.

[sergey-tihon]

@nojaf @yisusalanpng here I also a little bit surprised

    inherit SwaggerSchemaParseException(sprintf
                                             "Value `%s` is not allowed for field `%s`(See %s for more details).\nObject:%A"
                                             value
                                             field
                                             specLink
                                             obj)

why Fantoms does not insert line break before sprintf?

[nojaf]

There might have been an offset rule for that pre-F# 6 relaxations.
To produce valid code, we needed to put all the code after the (.
This doesn't seem a problem anymore and could be improved.
@yisusalanpng could you please report this issue using the online tool?

[nojaf]

@sergey-tihon is this good to go?
The reported bug and style guide questions won't be solved overnight (and are most likely present in the current version of Fantomas anyway).

[sergey-tihon]

Thank you @yisusalanpng & @nojaf for this PR

Would be nice if you can try to format https://github.com/fsprojects/FSharp.TypeProviders.SDK as well.
I believe that Fantomas still fails to parse https://github.com/fsprojects/FSharp.TypeProviders.SDK/blob/master/src/ProvidedTypes.fs

[nojaf]

Ah shoot, this is already merged. @yisusalanpng I released alpha 11 on Friday. Would you mind making another PR?

[nojaf]

Great, we can take a look at that as well.