feat(layout): add Size::ZERO and Position::ORIGIN constants (#1253)

src/layout/position.rs

@@ -40,6 +40,9 @@ pub struct Position {
 }
 
 impl Position {
+    /// Position at the origin, the top left edge at 0,0
+    pub const ORIGIN: Self = Self { x: 0, y: 0 };
+
     /// Create a new position
     pub const fn new(x: u16, y: u16) -> Self {
         Self { x, y }

src/layout/size.rs

@@ -17,6 +17,9 @@ pub struct Size {
 }
 
 impl Size {
+    /// A zero sized Size
+    pub const ZERO: Self = Self::new(0, 0);
+
     /// Create a new `Size` struct
     pub const fn new(width: u16, height: u16) -> Self {
         Self { width, height }