Fix test examples

[JulianGCalderon]

In the array example, the mut keyword was missing.

In the hello world example, the type checker doesn't allow to assign a 'char' to an u8. So i converted it to it's ascii code.

[github-actions[bot]]

Benchmarking factorial

Compiling factorial (factorial.con) Finished release in 30.956811ms Running 5000000 iterations Using input value: 20 Concrete Result = 2432902008176640000 Time taken : 59.17 ms Rust Result = 2432902008176640000 Time taken : 60.08 ms

Benchmarking fib

Compiling fib (fib.con) Finished release in 26.543467ms Running 5000 iterations Using input value: 20 Concrete Result = 6765 Time taken : 136.22 ms Rust Result = 6765 Time taken : 85.20 ms

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 61.73%. Comparing base (20cfd8d) to head (16fda9f). Report is 2 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #133 +/- ## ========================================== - Coverage 61.78% 61.73% -0.06% ========================================== Files 25 25 Lines 4394 4497 +103 ========================================== + Hits 2715 2776 +61 - Misses 1679 1721 +42 ```

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