Correct matching of expected source paths for nested package declarations

[odisseus]

Checklist

• [x] I have filed an issue about this change and discussed potential changes with the maintainers.
• [ ] I have received the approval from the maintainers to make this change.
• [x] This is not a stylistic, refactoring, or cleanup change.

Please note that the maintainers will not be reviewing this change until all checkboxes are ticked. See the Contributions section in the README for more details.

Discussion thread for this change

Issue number: #3433

Description of this change

This pull request adds partial support for nested package declarations in Scala.

[sgowroji]

Hello @odisseus, Could you please respond to above review comments. Thanks!