Parser should emit a single diagnostic if both open and close quote are missing from string literal

[ahoppen]

Issue Kind

Bad Diagnostic Produced

Source Code

@_expose(Cxx, baz) func foo() {}

Description

From https://github.com/apple/swift-syntax/pull/1688/files#r1201105564

In the above example the parser produces two diagnostics: One for the missing opening " before baz and one for the missing closing " after baz. It should emit a single diagnostic instead that offers to add both.

[ahoppen]

Tracked in Apple’s issue tracker as rdar://109685043

[TTOzzi]

Hello @kimdv @ahoppen ! 👋
May I attempt to resolve this issue?

[kimdv]

Go for it @TTOzzi 🙌

[TTOzzi]

Thank you! 😉