Fix broken links in contributor_docs/documentation_style_guide.md

[aleannab]

Most appropriate sub-area of p5.js?

• [ ] Accessibility
• [ ] Color
• [ ] Core/Environment/Rendering
• [ ] Data
• [ ] DOM
• [ ] Events
• [ ] Image
• [ ] IO
• [ ] Math
• [ ] Typography
• [ ] Utilities
• [ ] WebGL
• [ ] Build process
• [ ] Unit testing
• [ ] Internationalization
• [ ] Friendly errors
• [X] Other (specify if possible)

p5.js version

v1.10.0 (latest)

Web browser and version

Firefox v130.0, though would affect all.

Operating system

Windows, though would affect all.

Steps to reproduce this

Steps:

1. Go to: https://github.com/processing/p5.js/blob/main/contributor_docs/documentation_style_guide.md
2. Click on respective links (listed in table below).
3. Get a 404 error.

Solutions:

Replace listed broken links to the correct links. I did look through the p5.js-website repo, and couldn't find matching file paths.

Source link text:	Current link:	Suggested link:
src/data/examples/assets	https://github.com/processing/p5.js-website/tree/main/src/data/examples	???
src/templates/pages/reference/assets	https://github.com/processing/p5.js-website/tree/main/src/templates/pages/reference/assets	???
src/assets/learn	https://github.com/processing/p5.js-website/tree/main/src/assets/learn	???