Floating toolbar for Markdown fieldtype

[duncanmcclean]

When using Bard, you can choose to enable a "floating toolbar", which keeps the toolbar in view as you scroll down in the content, allowing you to access buttons like bold/italic/links.

However, the Markdown fieldtype doesn't have a "floating toolbar" feature which means that you need to scroll back up when you want to open the asset selector or create a link.