Deprecated classes `JavalangImproved` and `Lines` remain in the codebase

[ivanovmg]

There are deprecated classes JavalangImproved and Lines that are deprecated, with the later one used by the former.
Both need to be removed as presumably not used anywhere else.

• Lines - https://github.com/cqfn/aibolit/blob/master/aibolit/utils/lines.py
• JavalangImproved - https://github.com/cqfn/aibolit/blob/master/aibolit/utils/java_parser.py

[ivanovmg]

@yegor256 FYI

[yegor256]

@ivanovmg indeed a bug, thanks

[0crat]

@ivanovmg Congratulations on your bug report! 🐛 As per our policy, you've earned the full 12 points bonus. Your keen eye helps enhance our project's quality. Keep spotting issues and don't hesitate to report them. Your current balance stands at +262. Great job contributing to our project's improvement!

[ivanovmg]

Closing via #841