Fix MSVC compilation warnings

[Hardcode3]

The following MSVC compiler warning must be fixed:

  test_pmg_generate_pseudo_legal_moves.cpp
D:\a\BitBishop\BitBishop\tests\bitbishop\helpers\moves.hpp(25,23): warning C4244: 'return': conversion from '__int64' to 'int', possible loss of data [D:\a\BitBishop\BitBishop\build\msvc_debug\tests\test_pmg_generate_pseudo_legal_moves.vcxproj]
  (compiling source file '../../../tests/bitbishop/moves/pawn_move_generator/test_pmg_generate_pseudo_legal_moves.cpp')
      D:\a\BitBishop\BitBishop\tests\bitbishop\helpers\moves.hpp(25,23):
      the template instantiation context (the oldest one first) is
          D:\a\BitBishop\BitBishop\tests\bitbishop\helpers\moves.hpp(99,10):
          see reference to function template instantiation 'int count_if<count_moves_from::<lambda_1>>(const std::vector<Move,std::allocator<Move>> &,Pred)' being compiled
          with
          [
              Pred=count_moves_from::<lambda_1>
          ]