Deal with F# 9

[nojaf]

So, F# 9 is coming in November!

There are some new syntax features that we don't support yet:

• [RFC FS-1060] Nullness checking dotnet/fsharp#15181
• Allow access modifiers to auto properties getters and setters dotnet/fsharp#16861

In this PR, I'm updating the compiler (syncing the source dependency) and making the bare minimum adjustments to support the new syntax. This means I'm not focusing on style and will be winging it based on best effort.

To-do:

• Pass all existing tests
• Nullness tests
• Access modifiers for auto-properties' getters and setters tests
• Sanity check: format dotnet/fsharp to ensure everything is okay

Open questions:

• I would like to bump FSharp.Core and StreamJsonRpc, but I'm unsure of the consequences. I'm most concerned about Update FSharp.Core fantomas-for-vs#55.
• We should probably aim for a major version bump here and increase the TFM of the tool to net8.0.
• Should we reconsider anything else if we proceed with a major version bump?

Follow up:

• Nullness issue - Bar trivia in SynType.WithNull dotnet/fsharp#17720
• Nullness issue - trivia for SynTypeConstraint.WhereTyparNotSupportsNull dotnet/fsharp#17721

//cc @dawedawe @josh-degraw

[nojaf]

Not sure why, but the logger was no longer printing anything to the stdout.
No clue why, but using the static logger works.

[dawedawe]

In the name of all Fantomas users: Thank you!