Fix the pawn unit tests

moves/src/en_passant.rs

@@ -3,7 +3,7 @@
 use chessfriend_core::{Rank, Square};
 
 /// En passant information.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub struct EnPassant {
     target: Square,
     capture: Square,
@@ -39,10 +39,12 @@ impl EnPassant {
         }
     }
 
+    /// The square the capturing piece will move to.
     pub fn target_square(&self) -> Square {
         self.target
     }
 
+    /// The square on which the captured pawn sits.
     pub fn capture_square(&self) -> Square {
         self.capture
     }