fix(redis): make xadd fields use SupportsItems (#10780)

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

stubs/redis/@tests/test_cases/check_xadd.py

@@ -0,0 +1,16 @@
+from typing import TypedDict
+
+import redis
+
+
+class RedisStreamData(TypedDict):
+    foo: str
+    bar: bytes
+
+
+def check_xadd(r: redis.Redis[str]) -> None:
+    # check that TypedDicts are accepted for the `fields` parameter of `xadd()`
+    #
+    # N.B. the `pyright: ignore` is not part of the test,
+    # it's just because the return type is currently unannotated
+    r.xadd("stream", fields=RedisStreamData({"foo": "bar", "bar": b"foo"}))  # pyright: ignore[reportUnknownMemberType]