Also, the change in insert-hyperlink (from `this.linkUrl.indexOf("http") === -1` to `!this.linkUrl.startsWith("http")`) was intentional fix: we don't want to prevent users from looking up topics with http in their titles.
Major changes included:
- better support for screen readers
- trapping focus in modals
- better tabbing order in composer
- alerts on no content found/number of items found
- better autofocus in modals
- mini-tag-chooser is now a multi-select component
- each multi-select-component will now display selection on one row
This reverts commit 20780a1eee.
* SECURITY: re-adds accidentally reverted commit:
03d26cd6: ensure embed_url contains valid http(s) uri
* when the merge commit e62a85cf was reverted, git chose the 2660c2e2 parent to land on
instead of the 03d26cd6 parent (which contains security fixes)
