Fix Vectorized<double>::next_after SVE compilation (pytorch#136388)

Should have called [`Sleef_nextafterdx_sve`](https://sleef.org/2-references/libm/aarch64#vectorized-double-precision-function-for-obtaining-the-next-representable-fp-value) rather than [`Sleef_nextafterfx_sve`](https://sleef.org/2-references/libm/aarch64#vectorized-single-precision-function-for-obtaining-the-next-representable-fp-value) to get vectorized `nextafter` for double precision rather than single precision values

This fixes a compilation issue introduced by pytorch#119571 and exposed by pytorch#133339

Pull Request resolved: pytorch#136388
Approved by: https://github.com/kit1980

Author: malfet

aten/src/ATen/cpu/vec/sve/vec_double.h

@@ -261,7 +261,7 @@ template <> class Vectorized<double> {
   Vectorized<double> nextafter(const Vectorized<double> &b) const {
     USE_SLEEF(
       {
-        return Vectorized<double>(Sleef_nextafterfx_sve(values, b));
+        return Vectorized<double>(Sleef_nextafterdx_sve(values, b));
       },
       {
         __at_align__ double tmp[size()];