doc: minor updates re: type aliases, crate to 0.5.1

Signed-off-by: Stephen Waits <steve@waits.net>

src/network_coordinate.rs

@@ -56,6 +56,20 @@ pub struct NetworkCoordinate<const N: usize> {
     error: f32,
 }
 
+// type aliases for convenience
+
+/// A 2D [`NetworkCoordinate`]. Includes a 2D Euclidean position and a height.
+///
+/// This type alias is just for convenience. It's functionally equivalent to
+/// `NetworkCoordinate<2>`.
+pub type NetworkCoordinate2D = NetworkCoordinate<2>;
+
+/// A 3D [`NetworkCoordinate`]. Includes a 3D Euclidean position and a height.
+///
+/// This type alias is just for convenience. It's functionally equivalent to
+/// `NetworkCoordinate<3>`.
+pub type NetworkCoordinate3D = NetworkCoordinate<3>;
+
 //
 // **** Implementations ****
 //