[PATCH 04/12] qapi: update type hint for types_seen

In preparation for upgrading Python to 3.12+, adjust the type hint on
types_seen to prevent mypy from chirping about an unknown type for
this variable.

Why didn't this trigger earlier? A mystery for the ages.

Signed-off-by: John Snow <[email protected]>
---
 scripts/qapi/types.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
index 2bf75338283..b87377c6474 100644
--- a/scripts/qapi/types.py
+++ b/scripts/qapi/types.py
@@ -34,7 +34,7 @@
 
 # variants must be emitted before their container; track what has already
 # been output
-objects_seen = set()
+objects_seen: set[str] = set()
 
 
 def gen_enum_lookup(name: str,
-- 
2.55.0