[web-animations-1] Broken references in Web Animations

[dontcallmedom-bot]

While crawling Web Animations, the following links to other specifications were detected as pointing to non-existing anchors, which should be fixed:

• https://heycam.github.io/webidl/#dfn-present
• https://w3c.github.io/hr-time/#time-origin
• https://w3c.github.io/hr-time/#domhighrestimestamp

_{This issue was detected and reported semi-automatically by Strudy based on data collected in webref.}