Implement std::fmt::Display for iced::Radians (#2446)

* Implement `std::fmt::Display` for Radians

* Add ` rad` to the end of all displayed strings.

Co-authored-by: Héctor Ramón <hector0193@gmail.com>

---------

Co-authored-by: Héctor Ramón <hector0193@gmail.com>

core/src/angle.rs

@@ -1,6 +1,7 @@
 use crate::{Point, Rectangle, Vector};
 
 use std::f32::consts::{FRAC_PI_2, PI};
+use std::fmt::Display;
 use std::ops::{Add, AddAssign, Div, Mul, RangeInclusive, Rem, Sub, SubAssign};
 
 /// Degrees
@@ -237,3 +238,9 @@ impl PartialOrd<f32> for Radians {
         self.0.partial_cmp(other)
     }
 }
+
+impl Display for Radians {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{} rad", self.0)
+    }
+}