Implement focus_previous operation

src/widget.rs

@@ -215,6 +215,14 @@ pub use svg::Svg;
 use crate::Command;
 use iced_native::widget::operation;
 
+/// Focuses the previous focusable widget.
+pub fn focus_previous<Message>() -> Command<Message>
+where
+    Message: 'static,
+{
+    Command::widget(operation::focus_previous())
+}
+
 /// Focuses the next focusable widget.
 pub fn focus_next<Message>() -> Command<Message>
 where