python/qemu/qmp/legacy: Replace 'returns-whitelist' with the correct type

'returns-whitelist' has been renamed to 'command-returns-exceptions' in
commit b86df3747848 ("qapi: Rename pragma *-whitelist to *-exceptions").

Message-Id: <20220711095721.61280-1-thuth@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
diff --git a/python/qemu/qmp/legacy.py b/python/qemu/qmp/legacy.py
index 03b5574..1951754 100644
--- a/python/qemu/qmp/legacy.py
+++ b/python/qemu/qmp/legacy.py
@@ -50,7 +50,7 @@
 
 # QMPMessage can be outgoing commands or incoming events/returns.
 # QMPReturnValue is usually a dict/json object, but due to QAPI's
-# 'returns-whitelist', it can actually be anything.
+# 'command-returns-exceptions', it can actually be anything.
 #
 # {'return': {}} is a QMPMessage,
 # {} is the QMPReturnValue.