New tokens and bug fix

[Pacsfury]

Add compound assignment, increment/decrement, and shift operators to the lexer

Summary

Extends the lexer to recognize compound assignment operators, increment/decrement operators, and bitwise shift operators, which were previously unsupported. Also fixes an unterminated string literal bug where a missing closing quote followed by a newline was silently accepted instead of raising a diagnostic.

Changes

token.hpp

• Added 12 new token_kind enumerators:
  • Compound assignment: plus_equal, minus_equal, star_equal, slash_equal, modulo_equal, caret_equal, pipe_equal, ampersand_equal
  • Increment/decrement: plus_plus, minus_minus
  • Shifts: less_less, greater_greater
• Added corresponding cases to token_kind_to_string.

lexer.cpp

• Updated scan_token to recognize the new operators via match() chains (e.g. += before ++ before +), covering:
  • +, -, *, /, %, ^, |, & compound assignment forms
  • ++, --
  • <<, >>
• Fixed string(): unterminated string detection now also triggers when a newline is hit before the closing ", not just at EOF. Previously this case fell through and silently consumed the newline as if it were the closing quote, producing a corrupted token with no diagnostic.

[spatulari]

Thank you for the contribution, but the lexer is going through some massive changes right now, could you readd those tokens once it's finished? Sorry. (Check pr #33 )

[Pacsfury]

Ok. I will convert this to draft until PR #33 is merged and I will readd everything