fix: Broken links in examples

[nschonni]

Pulled the fixes from https://github.com/w3c/aria-practices/pull/2147 to a separate PR so they can land ahead of any review of the infrastrucutre changes

[nschonni]

Note that this is failing now with the redesign, because there are links to pages that don't exist in this repo

  [404] patterns/
  [404] practices/landmark-regions/
  [404] practices/names-and-descriptions/
  [404] practices/

[mcking65]

Closing b/c all fixed during #2417 restructuring.