Improve diagnostics marked with TODO in `Tests/SwiftParser/translated`

There are ~150 TODOs left in the test cases where diagnostics from the C++ parser are superior to the ones generated by SwiftParser. Those should be fixed.

Some of these TODOs are marked as “good first issue” and fixing those should be a good starting point to get started with the swift-syntax codebase.

Here’s a list of the tests that still have TODOs remaining. If you’ve got commit access to the repository and are working on one of them, mark them as ticked and add your named to assign them to you. If you don’t have commit access, comment on this issue and I’ll update the list to assign an issue to you.

- [x] `testAvailabilityQueryUnavailability34a` @CippoX
- [x] `testDiagnoseAvailability17` @kimdv
- [x] `testDiagnoseAvailability20` @kimdv
- [x] `testDiagnoseAvailability21` @kimdv
- [x] `testEffectfulProperties12` @StevenWong12
- [x] `testEffectfulProperties13` @StevenWong12
- [x] `testIfconfigExpr17`
- [x] `testIfconfigExpr22`
- [x] `testIfconfigExpr24`
- [x] `testIfconfigExpr25`
- [x] `testIfconfigExpr27`
- [x] `testIfconfigExpr28`
- [x] `testIfconfigExpr30`
- [x] `testOperatorDecl6` @StevenWong12
- [x] `testOperatorDecl7` @StevenWong12
- [x] `testOperatorDecl8` @StevenWong12
- [ ] `testOperatorDecl21` @StevenWong12
- [ ] `testRecovery17`
- [ ] `testRecovery19`
- [ ] `testRecovery23 `
- [ ] `testRecovery25`
- [ ] `testRecovery28`
- [x] `testRecovery49`
- [x] `testRecovery63` (good first issue)
- [x] `testRecovery64` (good first issue)
- [x] `testRecovery98c` @kimdv
- [x] `testRecovery98d` @kimdv
- [x] `testRecovery98e` @kimdv
- [x] `testRecovery98f` @kimdv
- [x] `testRecovery98` @kimdv
- [x] `testRecovery99` @kimdv
- [x] `testRecovery100` @kimdv
- [x] `testRecovery10`
- [x] `testRecovery102` @CippoX
- [x] `testRecovery103`@CippoX
- [x] `testRecovery104`@CippoX
- [x] `testRecovery110` @kimdv
- [x] `testRecovery121` @kimdv
- [x] `testRecovery125` @kimdv
- [x] `testRecovery126` @kimdv
- [x] `testRecovery127` @kimdv
- [x] `testRecovery128` @kimdv
- [x] `testRecovery129` @kimdv
- [x] `testRecovery130` @kimdv
- [x] `testRecovery131` @kimdv
- [x] `testRecovery136` @ahoppen
- [x] `testRecovery137` @ahoppen
- [x] `testRecovery151` @kimdv
- [x] `testRecovery153` @kimdv
- [x] `testRecovery157` @CippoX
- [x] `testRecovery163 ` @kimdv
- [x] `testRecovery164` @kimdv
- [x] `testRecovery165`
- [ ] `testRecovery169`
- [x] `testRecovery176` @kimdv
- [x] `testRecovery177` @kimdv
- [x] `testRecovery181`
- [ ] `testTrailingClosures14`