Toggling NSSplitView’s pane with animation.

NSSplitView-toggle-pane.swift

@objc func toggleMainView(_ sender: Any) {
	let splitViewItem: NSSplitViewItem = self.splitViewItems[0]
	splitViewItem.animator().isCollapsed = !splitViewItem.isCollapsed
}

@objc func toggleInspector(_ sender: Any) {
	let splitViewItem: NSSplitViewItem = self.splitViewItems[1]
	splitViewItem.animator().isCollapsed = !splitViewItem.isCollapsed
}