[3.8] bpo-38218: Doc: Corrected syntax for return annotation (GH-16265)…

… (GH-16274)

Signed-off-by: Jason Plurad <pluradj@us.ibm.com>
(cherry picked from commit 9ab6038)

Co-authored-by: Jason Plurad <pluradj@us.ibm.com>

Doc/tutorial/errors.rst

@@ -353,7 +353,7 @@ If a :keyword:`finally` clause is present, the :keyword:`finally` clause will ex
 
 For example::
 
-   >>> def bool_return(): -> bool:
+   >>> def bool_return():
    ...     try:
    ...         return True
    ...     finally: