DOC: Add _dunder_array reference

Author: mtsokol

doc/source/numpy_2_0_migration_guide.rst

@@ -423,7 +423,7 @@ The :ref:`copy keyword behavior changes <copy-keyword-changes-2.0>` in
 * For any ``__array__`` method on a non-NumPy array-like object, ``dtype=None``
   and ``copy=None`` keywords must be added to the signature - this will work with older
   NumPy versions as well (although older numpy versions will never pass in ``copy`` keyword).
-  If the keywords are actually used in the ``__array__`` method implementation, then for:
+  If the keywords are added to the ``__array__`` signature, then for:
 
   * ``copy=True`` and any ``dtype`` value always return a new copy,
   * ``copy=None`` create a copy if required (for example by ``dtype``),

doc/source/user/basics.interoperability.rst

@@ -113,6 +113,8 @@ We can check that ``arr`` and ``new_arr`` share the same data buffer:
  array([1000, 2, 3, 4])
 
 
+.. _dunder_array.interface:
+
 The ``__array__()`` method
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 

numpy/_core/_add_newdocs.py

@@ -2954,6 +2954,9 @@
     parameter. The method returns a new array for ``copy=True``, regardless of
     ``dtype`` parameter.
 
+    A more detailed explanation of the ``__array__`` interface
+    can be found in :ref:`dunder_array.interface`.
+
     """))