DOC: Remove "current" from byte-order note and expand it slightly (numpy#22521)

We don't preserve non-native byte-order and we have no wish to do so.
(If someone disagrees, they better wite a NEP ;))
Spell it out, and thus:

closes numpygh-1866

Co-authored-by: Sebastian Berg <[email protected]>

Author: seberg

doc/source/user/byteswapping.rst

@@ -61,13 +61,15 @@ is also big-endian).  However, sometimes you need to flip these around.
 
 .. warning::
 
-    Scalars currently do not include byte order information, so extracting
-    a scalar from an array will return an integer in native byte order.
-    Hence:
+    Scalars do not include byte order information, so extracting a scalar from
+    an array will return an integer in native byte order.  Hence:
 
     >>> big_end_arr[0].dtype.byteorder == little_end_u4[0].dtype.byteorder
     True
 
+    NumPy intentionally does not attempt to always preserve byte-order
+    and for example converts to native byte-order in `numpy.concatenate`.
+
 Changing byte ordering
 ======================