Allow setting up "ID" or "TITLE" attribute on structured text elements

In order to being able to have “internal” document links, it would be good we have option to setup id or title attributes on at least headings in the structured text so that we can link internally to this section using <a href="#id">Some link</a>.

A great addition to this feature would be that Structured text field would have a GraphQL capability to fetch structure text field Headings with ID/Title attribute as an separate array. This would then be very easy to generate table of contents with internal links…

Something like (see the content section):

query Post {
  blogPost {
    content {
      blocks { .. }
      links { .. }