gh-137668: Document that ord() supports also bytes and bytearray

Doc/library/functions.rst

@@ -1562,13 +1562,18 @@ are always available.  They are listed here in alphabetical order.
    .. versionchanged:: 3.11
       The ``'U'`` mode has been removed.
 
-.. function:: ord(c)
+.. function:: ord(character, /)
 
-   Given a string representing one Unicode character, return an integer
+   The argument must be a one-character string or a :class:`bytes` or
+   :class:`bytearray` object of length 1.
+   If it is a one-character string, return an integer
    representing the Unicode code point of that character.  For example,
    ``ord('a')`` returns the integer ``97`` and ``ord('€')`` (Euro sign)
    returns ``8364``.  This is the inverse of :func:`chr`.
 
+   If the argument is a :class:`!bytes` or :class:`!bytearray` object of
+   length 1, return an integer value of its element.
+
 
 .. function:: pow(base, exp, mod=None)
 

Python/bltinmodule.c

@@ -2118,15 +2118,18 @@ builtin_oct(PyObject *module, PyObject *number)
 /*[clinic input]
 ord as builtin_ord
 
-    c: object
+    character as c: object
     /
 
 Return the Unicode code point for a one-character string.
+
+Return the value of the first byte for a bytes or bytearray object of
+length 1.
 [clinic start generated code]*/
 
 static PyObject *
 builtin_ord(PyObject *module, PyObject *c)
-/*[clinic end generated code: output=4fa5e87a323bae71 input=3064e5d6203ad012]*/
+/*[clinic end generated code: output=4fa5e87a323bae71 input=99e491d094680598]*/
 {
     long ord;
     Py_ssize_t size;