Add toJSON() to PerformanceTiming and PerformanceNavigation

[teoli2003]

I used: https://developer.mozilla.org/en-US/docs/Web/API/PerformanceEventTiming/toJSON as the template.

I didn't add an example as:

• these interfaces are deprecated
• all properties/methods documented for these interfaces don't have one.

Crafting new examples for these interfaces would have be a loss of time.

This is part of openwebdocs/project#152

[github-actions]

Preview URLs

• /en-US/docs/Web/API/PerformanceNavigation/toJSON
• /en-US/docs/Web/API/PerformanceNavigation
• /en-US/docs/Web/API/PerformanceTiming/toJSON
• /en-US/docs/Web/API/PerformanceTiming

External URLs (2)

URL: /en-US/docs/Web/API/PerformanceNavigation/toJSON
Title: PerformanceNavigation.toJSON()

• https://w3c.github.io/navigation-timing/ (1 time) (Note! This may be a new URL 👀)

---

URL: /en-US/docs/Web/API/PerformanceTiming/toJSON
Title: PerformanceTiming.toJSON()

• https://w3c.github.io/navigation-timing/ (1 time) (Note! This may be a new URL 👀)

(comment last updated: 2023-02-03 12:29:23)

[Elchi3]

Great, thank you! I agree, no need to provide examples here. Some suggestions but otherwise LGTM.