chore: add links to policy

Author: frihetselsker

capsules/core/src/virtualizers/virtual_uart.rs

@@ -237,7 +237,7 @@ impl<'a, P: SelectionPolicy<&'a UartDevice<'a, P>>> MuxUart<'a, P> {
     /// from the list of devices in the virtualizer.
     ///
     /// For the default implementation, please refer to `new` function
-    /// which uses `InsertionFirstPolicy` selection policy.
+    /// which uses [`InsertionFirstPolicy`] selection policy.
     pub fn new_with_policy(
         uart: &'a dyn uart::Uart<'a>,
         buffer: &'static mut [u8],