config: allow retrieving the modes

src/ifs/wl_output.rs

@@ -66,6 +66,7 @@ pub struct WlOutputGlobal {
     pub pos: Cell<Rect>,
     pub output_id: Rc<OutputId>,
     pub mode: Cell<backend::Mode>,
+    pub modes: Vec<backend::Mode>,
     pub node: CloneCell<Option<Rc<OutputNode>>>,
     pub width_mm: i32,
     pub height_mm: i32,
@@ -96,6 +97,7 @@ impl WlOutputGlobal {
         state: &Rc<State>,
         connector: &Rc<ConnectorData>,
         x1: i32,
+        modes: Vec<backend::Mode>,
         mode: &backend::Mode,
         manufacturer: &str,
         product: &str,
@@ -122,6 +124,7 @@ impl WlOutputGlobal {
             pos: Cell::new(Rect::new_sized(x1, 0, width, height).unwrap()),
             output_id,
             mode: Cell::new(*mode),
+            modes,
             node: Default::default(),
             width_mm,
             height_mm,