/*
* call-seq:
* dvector.sinh -> a_dvector
*
* Returns of copy of _dvector_ with entry x replaced by sinh(x).
*
* a = Dvector[ 0.1, -0.2, 0.3 ]
* a.sinh -> Dvector[ sinh(0.1), sinh(-0.2), sinh(0.3) ]
*/
VALUE dvector_sinh(VALUE ary) {