Certain syntaxes in ruby cause extraction errors

The following ruby code causes an extraction error when parsed.

```ruby
def foo(bar: nil) = raise NotImplementedError
```

The error message is as follows.

```
Error: Extraction failed in [filepath] with error A parse error occurred. Check the syntax of the file. If the file is invalid, correct the error or exclude the file from analysis.
```

This code is correct ruby syntax.
This problem was reproduced with CodeQL version 2.4.5.

Reproduce the extraction failure with the Ruby snippet in the issue using CodeQL 2.4.5 or a current checkout. No source file, test, or entry point is named, so first locate the Ruby extraction and parsing tests, then add coverage for this valid syntax and confirm extraction succeeds without the parse error.

Rédigé par le modèle d'indexation à partir du texte de l'issue.