[3.12] Simpler example of shallow dict export of a dataclass (GH-117812) (#117862)

Simpler example of shallow dict export of a dataclass (GH-117812)
(cherry picked from commit f303651)

Co-authored-by: Gouvernathor <44340603+Gouvernathor@users.noreply.github.com>

Author: miss-islington

Doc/library/dataclasses.rst

@@ -362,7 +362,7 @@ Module contents
 
    To create a shallow copy, the following workaround may be used::
 
-     dict((field.name, getattr(obj, field.name)) for field in fields(obj))
+     {field.name: getattr(obj, field.name) for field in fields(obj)}
 
    :func:`!asdict` raises :exc:`TypeError` if ``obj`` is not a dataclass
    instance.