Add recommended VS Code extensions

What does this change?

This PR introduces a curated list of recommended Visual Studio Code extensions to the module. The aim is to standardize the development environment for all trainees, ensuring they have access to essential tools and features that enhance their learning experience, and save our mentors' time and energy.

Common Content?

This change does not directly modify the common content shared across modules but provides an essential resource that complements the existing curriculum. It ensures that all trainees, regardless of their module, have a consistent set of tools at their disposal.

[ ] Block/s

Common Theme?

[ ] Yes

Issue number: #368

Org Content?

Module

Checklist

[ ] I have read the contributing guidelines
[ ] I have checked my spelling and grammar with an automated tool
[ ] I have previewed my changes to check the markdown renders as I intend
[ ] I have run my code to check it works
[ ] My changes follow our Style Guide

Who needs to know about this?

@CodeYourFuture/itp-syllabus-team

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CodeYourFuture / Module-HTML-CSS