No `Workspace::leaves` method

[I60R]

This exists in Python's i3ipc and returns a Vec over windows assigned to workspace

[Madhur Ahuja]

Python's module calculates it and exposes it as method. There is no inbuilt method in i3 protocol to retrieve all the leaves of all workspaces.

[I60R]

Ok

    let mut workspaces: Vec<_> = outputs.as_slice().iter()
        .flat_map(|outputs| outputs.nodes.as_slice())
        .filter(|workspace| workspace.name.as_deref() != Some("__i3_scratch"))
        .collect();

did the job