Allow to create shortURL for page headings

[petrenkonikita112263]

At the time, the application allows the creation of a short URL for only page itself from the "More actions" menu. However, at some point, the page may have massive content with several headings even though the page will have a table of contents; at some point, users would be interested in sharing links to specific content by heading.

This feature may be implemented by introducing a new icon after the ✏ icon (on the right side) that will be displayed for each page heading. By using that, the user will receive the same short URL but for a heading.