fix: links to correct pages

[Zenkoina]

Description

Fixes various links related to form validation to point to more relevant pages (e.g. a link on the HTMLInputElement pointing to a property with the same name on the HTMLObjectElement page instead of the one on HTMLInputElement).

Motivation

Makes navigating between relevant pages easier.

Additional details

commit comments:
Zenkoina@d1151c2#r150674120
Zenkoina@d1151c2#r150674290

[github-actions]

Preview URLs (6 pages)

• /en-US/docs/Web/API/ElementInternals/setValidity
• /en-US/docs/Web/API/HTMLButtonElement/validity
• /en-US/docs/Web/API/HTMLInputElement
• /en-US/docs/Web/API/HTMLSelectElement/checkValidity
• /en-US/docs/Web/API/ValidityState/customError
• /en-US/docs/Web/API/ValidityState

Flaws (5)

Note! 4 documents with no flaws that don't need to be listed. 🎉

URL: /en-US/docs/Web/API/HTMLSelectElement/checkValidity
Title: HTMLSelectElement: checkValidity() method
Flaw count: 1

• macros:
  • /en-US/docs/Web/API/HTMLElement/invalid_event redirects to /en-US/docs/Web/API/HTMLInputElement/invalid_event

---

URL: /en-US/docs/Web/API/HTMLInputElement
Title: HTMLInputElement
Flaw count: 4

• macros:
  • /en-US/docs/Web/API/HTMLInputElement/align does not exist
  • /en-US/docs/Web/API/HTMLInputElement/dirName does not exist
  • /en-US/docs/Web/API/HTMLInputElement/incremental does not exist
  • /en-US/docs/Web/API/HTMLInputElement/useMap does not exist