Add Julia sample file and reference TypeCode recognition fix

[HasTheDev]

Fixes #4596

This PR adds a Julia sample file to the toolkit to verify proper language recognition.

Note: The core logic fix and unit tests for identifying .jl files as Julia have been submitted to the underlying typecode library here:
aboutcode-org/typecode#49

Tasks

• Reviewed contribution guidelines
• PR is descriptively titled 📑 and links the original issue above 🔗
• Tests pass -- look for a green checkbox ✔️ a few minutes after opening your PR
• Commits are in uniquely-named feature branch and has no merge conflicts 📁
• Updated documentation pages (if applicable)
• Updated CHANGELOG.rst (if applicable)

Signed-off-by: HasTheDev hassanazam2021@gmail.com

[AyanSinhaMahapatra]

Please reopen PR when you actually have some code, even though https://github.com/aboutcode-org/typecode/pull/49/changes is a PR, you can install the branch here and show your code works with tests.