Margin description is inconsistent with behavior

[prurph]

Describe the bug
The margin setting is described as "the size of margins between windows", however it also appears to apply at the screen edges and the top of the menubar.

It probably makes most sense to just change the wording, both because it's easier and because that's consistent with, e.g., a CSS declaration of margin: 10px.

Applications:
All applications

To Reproduce
Set window-margins: true and window-margin-size: 10. Leave all padding settings to 0.

Expected behavior
Windows to fully extend to screen edges and bottom of status bar, with margins only providing spacing between neighboring windows, or description to indicate margin applies to all window edges.

Versions:

• macOS: 14.1.1
• Amethyst: 0.20.0