feat(widget): add dropdown::multi list widget

src/theme/style/dropdown.rs

@@ -23,6 +23,8 @@ impl dropdown::menu::StyleSheet for Theme {
 
             selected_text_color: cosmic.accent.base.into(),
             selected_background: Background::Color(cosmic.primary.component.hover.into()),
+
+            description_color: cosmic.primary.component.on_disabled.into(),
         }
     }
 }

src/widget/dropdown/menu/appearance.rs

@@ -26,6 +26,8 @@ pub struct Appearance {
     pub selected_text_color: Color,
     /// Background when selected
     pub selected_background: Background,
+    /// Description text color
+    pub description_color: Color,
 }
 
 /// The style sheet of a menu.

src/widget/dropdown/mod.rs

@@ -5,6 +5,8 @@
 pub mod menu;
 pub use menu::Menu;
 
+pub mod multi;
+
 mod widget;
 pub use widget::*;