Update documentation links that now permanently redirect

[adamtheturtle]

What happens

The linkcheck hook fails, and it is not intermittent. Sphinx runs with warnings treated as errors, and several documentation links now return permanent redirects:

File	Link	Redirects to
docker line 49	https://developer.vuforia.com/target-manager	/auth/login?url=develop/databases
docker line 47	https://www.rfc-editor.org/rfc/rfc7231#section-3.1.1.5	https://www.rfc-editor.org/info/rfc7231/
contributing line 169	https://developer.vuforia.com/library/web-api/vuforia-query-web-api	/library/vuforia-engine/web-api/vuforia-query-web-api/
differences-to-vws line 88	https://developer.vuforia.com/library/web-api/cloud-targets-web-services-api#result-codes	/library/vuforia-engine/web-api/cloud-targets-web-services-api/
mock-api-reference line 1	https://www.python.org/dev/peps/pep-0544/#runtime-checkable-...	https://peps.python.org/pep-0544/

The name of the builder is: linkcheck
build finished with problems, 2 warnings (with warnings treated as errors).

Why it matters

This fails on every run, so it blocks pull requests whose own diffs are fine. #3324 is a one-line Dependabot bump and has been held up by this and by #3355 in alternation.

Notes

Vuforia appears to have moved its library under /library/vuforia-engine/, and the redirect drops the #result-codes anchor, so the replacement link may need a new anchor rather than a straight substitution. The target-manager link redirecting to a login page suggests it may no longer be reachable anonymously at all, and may want a different destination.

#3351 already uses the new-style developer.vuforia.com/library/vuforia-engine/web-api/vuforia-query-web-api/ form, so part of the change is in flight.