Fix parsing of annotation type with inner enum

[FnControlOption]

Checklist:

• [ ] All tests pass in CI.
• [ ] There are sufficient tests for the new fix/feature.
• [x] Grammar rules have not been renamed unless absolutely necessary.
• [x] The conflicts section hasn't grown too much.
• [x] The parser size hasn't grown too much (check the value of STATE_COUNT in src/parser.c).

Closes #83

[raghav-deepsource]

@maxbrunsfeld , this is stuck on ci like the others...