Fix typo in the dataclasses's doc (GH-8896)

Doc/library/dataclasses.rst

@@ -447,7 +447,7 @@ parameters to the generated :meth:`__init__` method, and are passed to
 the optional :meth:`__post_init__` method.  They are not otherwise used
 by dataclasses.
 
-For example, suppose a field will be initialzed from a database, if a
+For example, suppose a field will be initialized from a database, if a
 value is not provided when creating the class::
 
   @dataclass