[FEATURE] Unary operators

[cykna]

Summary

Implement a unary operators, such as +expr -expr, !expr ~expr

Problem

The language yet hasn't any kind of unary operators to define negative values, logical and bit not operators

Proposed Solution

Modify the Parser and the HIR to handle the unary operators with a new expression type.

Alternatives Considered

N/A

Impact Area

Mark the area most affected:

• syntax / language design
• frontend / parser
• frontend / checker
• middleend / IR
• docs / workflow
• tooling / CI
• other

Example

func negative(n: int): int = -n;

Extra Context

• Check on https://github.com/Slynx-Language/slynx/blob/main/frontend/src/parser/expr.rs to implement the unary operators
• Check on https://github.com/Slynx-Language/slynx/blob/main/frontend/src/checker/expr.rs for the type checking of the unary