bpo-42391: Clarify documentation of TestCase.assertIs (GH-23348)


Removing 'evaluate' makes it more consistent with other assertX entries.
(cherry picked from commit bd8c22e1fa8f8f6e31ee083a8b9321a2c324f02f)

Co-authored-by: Ram Rachum <ram@rachum.com>
diff --git a/Doc/library/unittest.rst b/Doc/library/unittest.rst
index 523e0e6..9fc6620 100644
--- a/Doc/library/unittest.rst
+++ b/Doc/library/unittest.rst
@@ -897,8 +897,7 @@
    .. method:: assertIs(first, second, msg=None)
                assertIsNot(first, second, msg=None)
 
-      Test that *first* and *second* evaluate (or don't evaluate) to the
-      same object.
+      Test that *first* and *second* are (or are not) the same object.
 
       .. versionadded:: 3.1