Small clean-up

Bench: 4321677

src/bitboard.h

@@ -212,6 +212,7 @@ constexpr Bitboard adjacent_files_bb(Square s) {
 inline Bitboard line_bb(Square s1, Square s2) {
 
   assert(is_ok(s1) && is_ok(s2));
+
   return LineBB[s1][s2];
 }
 
@@ -225,7 +226,9 @@ inline Bitboard line_bb(Square s1, Square s2) {
 /// interpose itself to cover the check or capture the checking piece.
 
 inline Bitboard between_bb(Square s1, Square s2) {
+
   assert(is_ok(s1) && is_ok(s2));
+
   return BetweenBB[s1][s2];
 }