[A11y] Inline links not visually distinct from text

[ritiupa]

axe-core flags link-in-text-block (serious) on /reference/ and /reference/p5/circle/. Inline links inside body text are only distinguishable by color. There is no underline or other visual indicator. This fails WCAG 1.4.1 (Use of Color).

Examples:
The p5.sound link in the intro paragraph on /reference/
The ellipseMode() link inside body text on /reference/p5/circle/

Steps to reproduce:

1. Go to /reference/ or /reference/p5/circle/
2. Run axe DevTools or npm run test:a11y
3. See link-in-text-block violation

Expected: inline links should be visually distinguishable without relying on color alone, for example by adding an underline.

I searched open and closed issues before filing. No existing issue covers this rule in this repo.

@coseeian, flagging for label review.

[coseeian]

Hi @ritiupa, thanks for bringing this up.

I’m actually aware of this one - it’s been on my radar. The reason I haven't opened a dedicated issue for it yet is that, while adding an underline is trivial from a purely engineering standpoint, the broader scope requires a discussion with the p5.js product owner. We need to evaluate whether making underlines the default is acceptable to the design direction of the entire site, or if we can potentially introduce an accessibility preference toggle, similar to what GitHub does.

Because of these larger product decision scope, I wanted to avoid opening a public issue that contributors might immediately jump into fixing before we have a defined direction.

I’ve assigned this to myself for now. I'll find time to work on this and sync with the product owners about their thoughts.