[BitBoard] Address a bunch of rust-analyzer suggestions

Add #[must_use] to many methods

bitboard/src/bitboard.rs

@@ -12,6 +12,7 @@ pub struct BitBoard(pub(crate) u64);
 
 macro_rules! moves_getter {
     ($getter_name:ident) => {
+        #[must_use]
         pub fn $getter_name(sq: Square) -> BitBoard {
             library::library().$getter_name(sq)
         }
@@ -22,32 +23,39 @@ impl BitBoard {
     pub const EMPTY: BitBoard = BitBoard(u64::MIN);
     pub const FULL: BitBoard = BitBoard(u64::MAX);
 
+    #[must_use]
     pub const fn empty() -> BitBoard {
         BitBoard(0)
     }
 
+    #[must_use]
     pub const fn new(bits: u64) -> BitBoard {
         BitBoard(bits)
     }
 
+    #[must_use]
     pub fn rank(rank: &u8) -> BitBoard {
         debug_assert!(*rank < 8);
         library::RANKS[*rank as usize]
     }
 
+    #[must_use]
     pub fn file(file: &u8) -> BitBoard {
         debug_assert!(*file < 8);
         library::FILES[*file as usize]
     }
 
+    #[must_use]
     pub fn ray(sq: Square, dir: Direction) -> &'static BitBoard {
         library::library().ray(sq, dir)
     }
 
+    #[must_use]
     pub fn pawn_attacks(sq: Square, color: Color) -> BitBoard {
         library::library().pawn_attacks(sq, color)
     }
 
+    #[must_use]
     pub fn pawn_pushes(sq: Square, color: Color) -> BitBoard {
         library::library().pawn_pushes(sq, color)
     }
@@ -58,16 +66,19 @@ impl BitBoard {
     moves_getter!(queen_moves);
     moves_getter!(king_moves);
 
+    #[must_use]
     pub const fn kingside(color: Color) -> &'static BitBoard {
         &library::KINGSIDES[color as usize]
     }
 
+    #[must_use]
     pub const fn queenside(color: Color) -> &'static BitBoard {
         &library::QUEENSIDES[color as usize]
     }
 }
 
 impl BitBoard {
+    #[must_use]
     pub const fn as_bits(&self) -> &u64 {
         &self.0
     }
@@ -82,6 +93,7 @@ impl BitBoard {
     /// assert!(!BitBoard::FULL.is_populated());
     /// assert!(!BitBoard::new(0b1000).is_populated());
     /// ```
+    #[must_use]
     pub const fn is_empty(&self) -> bool {
         self.0 == 0
     }
@@ -269,7 +281,7 @@ impl fmt::Display for BitBoard {
         let binary_ranks = format!("{:064b}", self.0)
             .chars()
             .rev()
-            .map(|c| String::from(c))
+            .map(String::from)
             .collect::<Vec<String>>();
 
         let mut ranks_written = 0;
@@ -279,7 +291,7 @@ impl fmt::Display for BitBoard {
 
             ranks_written += 1;
             if ranks_written < 8 {
-                write!(f, "\n")?;
+                writeln!(f)?;
             }
         }