Fixed #24520 -- Documented Widget.supports_microseconds

docs/ref/forms/widgets.txt

@@ -217,6 +217,17 @@ foundation for custom widgets.
                 >>> name.render('name', 'A name')
                 '<input name="name" type="text" value="A name" />'
 
+    .. attribute:: Widget.supports_microseconds
+
+       An attribute that defaults to ``True``. If set to ``False``, the
+       microseconds part of :class:`~datetime.datetime` and
+       :class:`~datetime.time` values will be set to ``0``.
+
+       .. versionadded:: 1.9
+
+           In older versions, this attribute was only defined on the date
+           and time widgets (as ``False``).
+
     .. method:: render(name, value, attrs=None)
 
         Returns HTML for the widget, as a Unicode string. This method must be
@@ -491,6 +502,10 @@ These widgets make use of the HTML elements ``input`` and ``textarea``.
     format found in :setting:`DATETIME_INPUT_FORMATS` and respects
     :ref:`format-localization`.
 
+    By default, the microseconds part of the time value is always set to ``0``.
+    If microseconds are required, use a subclass with the
+    :attr:`~Widget.supports_microseconds` attribute set to ``True``.
+
 ``TimeInput``
 ~~~~~~~~~~~~~
 
@@ -508,6 +523,8 @@ These widgets make use of the HTML elements ``input`` and ``textarea``.
     format found in :setting:`TIME_INPUT_FORMATS` and respects
     :ref:`format-localization`.
 
+    For the treatment of microseconds, see :class:`DateTimeInput`.
+
 ``Textarea``
 ~~~~~~~~~~~~