Issue #16082: clarify the documentation of tostring[list] saying that it may…

Issue #16082: clarify the documentation of tostring[list] saying that it may generate a bytestring, depending on the given encoding.

Doc/library/xml.etree.elementtree.rst

@@ -433,9 +433,9 @@ Functions
    Generates a string representation of an XML element, including all
    subelements.  *element* is an :class:`Element` instance.  *encoding* [1]_ is
    the output encoding (default is US-ASCII).  Use ``encoding="unicode"`` to
-   generate a Unicode string.  *method* is either ``"xml"``,
-   ``"html"`` or ``"text"`` (default is ``"xml"``).  Returns an (optionally)
-   encoded string containing the XML data.
+   generate a Unicode string (otherwise, a bytestring is generated).  *method*
+   is either ``"xml"``, ``"html"`` or ``"text"`` (default is ``"xml"``).
+   Returns an (optionally) encoded string containing the XML data.
 
 
 .. function:: tostringlist(element, encoding="us-ascii", method="xml")
@@ -443,11 +443,11 @@ Functions
    Generates a string representation of an XML element, including all
    subelements.  *element* is an :class:`Element` instance.  *encoding* [1]_ is
    the output encoding (default is US-ASCII).  Use ``encoding="unicode"`` to
-   generate a Unicode string.  *method* is either ``"xml"``,
-   ``"html"`` or ``"text"`` (default is ``"xml"``).  Returns a list of
-   (optionally) encoded strings containing the XML data.  It does not guarantee
-   any specific sequence, except that ``"".join(tostringlist(element)) ==
-   tostring(element)``.
+   generate a Unicode string (otherwise, a bytestring is generated).  *method*
+   is either ``"xml"``, ``"html"`` or ``"text"`` (default is ``"xml"``).
+   Returns a list of (optionally) encoded strings containing the XML data.
+   It does not guarantee any specific sequence, except that
+   ``"".join(tostringlist(element)) == tostring(element)``.
 
    .. versionadded:: 3.2