Description of the Issue

The Preferences sub-page labelled Editing is getting a bit crowded.
Let's create a new sub-page and call it Margin/Border/Edge and move the appropriate Editing items there.
The gain will be that both sub-pages will then have a lot of room for future expansion.

For reference, see here: #8822 (comment)
And here: #8822 (comment)

The above is based upon Preferences UI in Notepad++ version 7.8.9