Bring parity to toolbars of the plain and rich text editors

There are currently some differences in the toolbars of the plain text and rich text editors.

plain text	rich text

Specifically:

• rte is missing "Add a collapsible section" in the main toolbar. It's currently "Details block" in the "More options" menu.
• pte is missing a separator between the "Add a quick action" and "Insert comment template".
• pte is missing a "More options" menu, which in the rte has "Code block", "Details block", "Horizontal rule", "Mermaid diagram", "PlantUML diagram", and "Table of contents".
• rte does not have a "Go to full screen" button