Add docs

Author: johnslavik

Doc/library/exceptions.rst

@@ -215,9 +215,18 @@ The following exceptions are the exceptions that are usually raised.
 
       The object that was accessed for the named attribute.
 
+   When possible, :attr:`name` and :attr:`obj` are set automatically
+   for failed attribute lookups.
+
    .. versionchanged:: 3.10
       Added the :attr:`name` and :attr:`obj` attributes.
 
+   .. versionchanged:: next
+      The default error message is now generated from :attr:`name` and
+      :attr:`obj` when both attributes are set and the exception was
+      constructed with no positional arguments, or with a single positional
+      argument equal to :attr:`name`.
+
 .. exception:: EOFError
 
    Raised when the :func:`input` function hits an end-of-file condition (EOF)