Add support for F# 8.0 features

[Jand42]

New language/FSharp.Core features: (See Announcing F# 8)

• Update to FSharp.Compiler.Service 43.8.100
• _.Property shorthand (should be handled by FCS without AST change)
  • Tests added
• Nested record field copy and update (should be handled by FCS without AST change)
  • Tests added
• while! - syntax sugar handled by FCS, uses already existing Bind+While methods
  • Tests added
• Extended string interpolation syntax - multiple $ now marks multiple { } needed. String interpolation macro needs to be updated
  • Tests added
• Use and compose string literals for printf and related functions (probably handled by FCS and we can extract string literal the same way, needs to be tested)
  • Tests added
• Arithmetic operators in literals - do we translate expression or compute literal? Both should work, but latter is optimal.
  • Tests added
• Type constraint intersection syntax - type system upgrade, should have no effect on us, but add test to be sure
  • Tests added
• Extended fixed bindings - WS has no support for fixed, it's just ignored
• Easier [<Extension>] method definition - syntax upgrade to test
  • Tests added
• Static members in interfaces - we already have support for same in C#, to bring over to F# ProjectReader
  • Tests added
• Static let in discriminated unions, records, structs, and types without primary constructors - should be handled by FCS but needs test. All static lets are hoisted to run on module initialization by F# semantics anyways
  • Tests added
• try-with within seq{},[] and [||] collection expressions - needs proxy for RuntimeHelpers.EnumerateTryWith and EnumerateFromFunctions
  • Tests added

[Tarmil]

I don't think while! needs new proxies actually: it is desugared into a combination of existing methods Bind, While, and mutable variables. Ie an expression like

while! cond do
    action

is desugared as if it was written

let! x = cond
let mutable x' = x
while x' do
    action
    let! x = cond
    x' <- x

[Jand42]

@Tarmil Thanks! Indeed, TDD would have discovered this, I skipped testing while! for some reason while I checked what try-with within seq{} does. I have seen comparing methods in RuntimeHelpers that we also miss EnumerateFromFunctions, but I can't see in dotnet/fsharp where it's actually used yet... maybe deprecated?