message: Update import path in pure canvas example
  In current version, `iced::pure::canvas` would be unresolved.
  It should be `iced::pure::widget::canvas`.
diff: @@ -32,7 +32,7 @@ use std::marker::PhantomData;
  /// # }
  /// # pub use iced_native::{Color, Rectangle, Theme};
  /// # }
  -/// use iced::pure::canvas::{self, Canvas, Cursor, Fill, Frame, Geometry, Path, Program};
  +/// use iced::pure::widget::canvas::{self, Canvas, Cursor, Fill, Frame, Geometry, Path, Program};
  /// use iced::{Color, Rectangle, Theme};
  ///
  /// // First, we define the data we need for drawing
  