📝 Update source examples and docs from Python 3.9 to 3.10 (#14900)

docs_src/custom_response/tutorial007_py310.py

@@ -0,0 +1,14 @@
+from fastapi import FastAPI
+from fastapi.responses import StreamingResponse
+
+app = FastAPI()
+
+
+async def fake_video_streamer():
+    for i in range(10):
+        yield b"some fake video bytes"
+
+
+@app.get("/")
+async def main():
+    return StreamingResponse(fake_video_streamer())