Add some help inside the Nodes tab page

To see what you can do inside a tab page, you need to look at the source code of the application. Because there is not a single hint on what the application can do.

Take a look at the source code on `./src/ui/edit.rs`, at the `action_edit` function. And edit that function so that when the user hits the "?" key inside the edit page, he will see an explanation of that page inside a widget (use the widget you will like the most) and this widget will tell you what this page does, and what the user can do on that page

Start in src/ui/edit.rs at the action_edit function and inspect how the edit page handles key input and displays widgets. Done when pressing ? inside the edit page shows a widget explaining what the page does and what actions are available.

Written by the indexing model from the issue text.