Parser error for `final get`

[AnthonyLatsis]

Description

We have a bespoke semantic analysis diagnostic for this case, but instead, we get a parser error.

swift/include/swift/AST/DiagnosticsSema.def

Lines 3965 to 3967 in 80a8a07

	ERROR(final_not_on_accessors,none,
	"only the %select{property|subscript}0 itself can be marked as 'final'"
	,(bool))

Reproduction

class C {
  var prop: Int {
    final get {}
  }
}

Expected behavior

Code should survive to semantic analysis.

Environment

Swift version 6.0-dev (LLVM c7c87ee42989d4b, Swift 8493312)

Additional information

No response