Menu entry for command 'application:close' is duplicated.

[jtpio]

The following warnings are logged in the dev tools console:

settingregistry.js:803 Menu entry for command 'filemenu:close-and-cleanup' is duplicated.
settingregistry.js:803 Menu entry for command 'application:close' is duplicated.

They likely come from the definition of the menu entries order in:

notebook/packages/application-extension/schema/menus.json

Lines 21 to 28 in 91dc119

	{
	"command": "filemenu:close-and-cleanup",
	"rank": 40
	},
	{
	"command": "application:close",
	"disabled": true
	}

This was added in #6937 to mimic the look of the classic notebook.