Update stan/math/fwd/scal/fun/ldexp.hpp
Update stan/math/fwd/scal/fun/ldexp.hpp

Co-Authored-By: Steve Bronder <0f2fb86a0f2d6cb94d34747e21234c0fe48b0ce5@gmail.com>
stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math