Add support for complex number subtraction (#526)

Author: kgryte

spec/API_specification/array_api/array_object.py

@@ -947,14 +947,16 @@ def __setitem__(self: array, key: Union[int, slice, ellipsis, Tuple[Union[int, s
 
     def __sub__(self: array, other: Union[int, float, array], /) -> array:
         """
-        Calculates the difference for each element of an array instance with the respective element of the array ``other``. The result of ``self_i - other_i`` must be the same as ``self_i + (-other_i)`` and must be governed by the same floating-point rules as addition (see :meth:`array.__add__`).
+        Calculates the difference for each element of an array instance with the respective element of the array ``other``.
+
+        The result of ``self_i - other_i`` must be the same as ``self_i + (-other_i)`` and must be governed by the same floating-point rules as addition (see :meth:`array.__add__`).
 
         Parameters
         ----------
         self: array
-            array instance (minuend array). Should have a real-valued data type.
+            array instance (minuend array). Should have a numeric data type.
         other: Union[int, float, array]
-            subtrahend array. Must be compatible with ``self`` (see :ref:`broadcasting`). Should have a real-valued data type.
+            subtrahend array. Must be compatible with ``self`` (see :ref:`broadcasting`). Should have a numeric data type.
 
         Returns
         -------

spec/API_specification/array_api/elementwise_functions.py

@@ -1826,14 +1826,16 @@ def sqrt(x: array, /) -> array:
 
 def subtract(x1: array, x2: array, /) -> array:
     """
-    Calculates the difference for each element ``x1_i`` of the input array ``x1`` with the respective element ``x2_i`` of the input array ``x2``. The result of ``x1_i - x2_i`` must be the same as ``x1_i + (-x2_i)`` and must be governed by the same floating-point rules as addition (see :meth:`add`).
+    Calculates the difference for each element ``x1_i`` of the input array ``x1`` with the respective element ``x2_i`` of the input array ``x2``.
+
+    The result of ``x1_i - x2_i`` must be the same as ``x1_i + (-x2_i)`` and must be governed by the same floating-point rules as addition (see :meth:`add`).
 
     Parameters
     ----------
     x1: array
-        first input array. Should have a real-valued data type.
+        first input array. Should have a numeric data type.
     x2: array
-        second input array. Must be compatible with ``x1`` (see :ref:`broadcasting`). Should have a real-valued data type.
+        second input array. Must be compatible with ``x1`` (see :ref:`broadcasting`). Should have a numeric data type.
 
     Returns
     -------