fix: proper error on unterminated quoted string

[Computerdores]

Summary

The tokenizer now returns a ParsingError when encountering an unterminated quoted string (e.g. "asd). This way the proper handling for ParsingErrors kicks in. (Also includes minor refactors to fix warnings in the associated files)

Tasks Completed

• Platforms Tested:
  • [x] Windows x86
  • [ ] Windows ARM
  • [ ] macOS x86
  • [ ] macOS ARM
  • [ ] Linux x86
  • [ ] Linux ARM
• Tested For:
  • [x] Basic functionality
  • [ ] PyInstaller executable