Broken references in MiniApp Manifest

[dontcallmedom-bot]

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

• [ ] https://www.w3.org/TR/appmanifest/#dfn-extension-point
• [ ] https://www.w3.org/TR/mediaqueries-4/#display-mode-minimal-ui

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