Broken references in Shared Storage API

[dontcallmedom-bot]

While crawling Shared Storage API, the following links to other specifications were detected as pointing to non-existing anchors:

• [ ] https://html.spec.whatwg.org/multipage/browsers.html#concept-opaque-origin

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

[jkarlin]

@pythagoraskitty PTAL!

[pythagoraskitty]

Thank you. Fixing in PR 85.