Reformat Edit menu items

I would like to create a separate section with dividers in the Glyphs app Edit menu above and below the three new menu items that are added by this plugin so that it appears as follows:

```
---divider---
FLM menu item 1
FLM menu item 2
FLM menu item 3
---divider---
```

Currently the menu items under the Edit menu are intermixed with other menu items. 