Add comparison for nextafter (#9)

Author: steff456

signatures/mathematical-functions-elementwise/nextafter.md

@@ -0,0 +1,42 @@
+# nextafter
+
+## NumPy
+
+```
+numpy.nextafter(x1, x2, out=None, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj]) → ndarray
+```
+
+## CuPy
+
+```
+cupy.nextafter(x1, x2, out=None, dtype=None) → ndarray
+```
+
+## dask.array
+
+```
+dask.array.nextafter(x1, x2, out=None, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj]) → ndarray
+```
+
+## JAX
+
+```
+jax.lax.nextafter(x1, x2) → ndarray
+```
+
+## MXNet
+
+```
+```
+
+## PyTorch
+
+```
+torch.nextafter(input, other, out=None) → Tensor
+```
+
+## TensorFlow
+
+```
+tf.math.nextafter( x1, x2, name=None ) → Tensor
+```