Fix doctest broken on 2021 edition

helix-term/src/compositor.rs

@@ -207,7 +207,7 @@ pub trait AnyComponent {
     ///
     /// ```rust
     /// use helix_term::{ui::Text, compositor::Component};
-    /// let boxed: Box<Component> = Box::new(Text::new("text".to_string()));
+    /// let boxed: Box<dyn Component> = Box::new(Text::new("text".to_string()));
     /// let text: Box<Text> = boxed.as_boxed_any().downcast().unwrap();
     /// ```
     fn as_boxed_any(self: Box<Self>) -> Box<dyn Any>;