[chore] Ensure that external link fragments are valid

[chalin]

Originally posted by @chalin in #6180 (comment):

Links into the spec pages are "localized" -- they become local paths rather than external URLs -- when published this repo, which is why anchor IDs are being checked. It seems like htmltest doesn't check anchor IDs on external links after all :-/ 🤷🏼‍♂️

I've just modified our test scripts to check anchors for external links too. Let's use this issue to track the necessary updates to fix links:

OTel website (this repo)

• Kubernetes operator page refers to API doc that can only be viewed as mostly unusable raw text view #6200
• [chore] Refresh refcache, fix external links with invalid fragments #6206
• Collector/building/... : links to specific authenticators are invalid #6234
  • [editorial] Add headings to configauth/README.md opentelemetry-collector#12309
• K8s operator API links are invalid #6237
• ...

Spec repo updates

• Copyedits to spring-boot-autoconfigure/README.md opentelemetry-java-instrumentation#13188
• [editorial] Use canonical URL to OpenMetrics repo opentelemetry-proto#617
• [editorial] Use canonical URL to OpenMetrics repo, and more opentelemetry-specification#4399
• [editorial] Fix invalid links and fragments semantic-conventions#1867
• [editorial] Invalid / retired link into Docker spec semantic-conventions#1865
  • [editorial] Fix link to example-image-manifest semantic-conventions#1881
• [editorial] Link-target gone, what should be used instead? semantic-conventions#1868
• [editorial] Fix invalid external links with fragments semantic-conventions#1882
• ...

Other

• Query parameter gets overly escaped when saved to the refcache wjdp/htmltest#239