Sync typeshed (#2684)

This is specifically against
python/typeshed@4603baaa6cd2c8c4d3a89c949d3232a17fb2c221 as requested by
@gvanrossum in python/typeshed#822 for the upcoming 0.470 release.

Tests pass.

typeshed

diff --git a/typeshed b/typeshed
index b369a3f..4603baa 160000
--- a/typeshed
+++ b/typeshed
@@ -1 +1 @@
-Subproject commit b369a3f2dbaadb5e8841d65f475a6c62659f597e
+Subproject commit 4603baaa6cd2c8c4d3a89c949d3232a17fb2c221