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

docs_src/response_headers/tutorial001_py310.py

@@ -0,0 +1,11 @@
+from fastapi import FastAPI
+from fastapi.responses import JSONResponse
+
+app = FastAPI()
+
+
+@app.get("/headers/")
+def get_headers():
+    content = {"message": "Hello World"}
+    headers = {"X-Cat-Dog": "alone in the world", "Content-Language": "en-US"}
+    return JSONResponse(content=content, headers=headers)

docs_src/response_headers/tutorial002_py310.py

@@ -0,0 +1,9 @@
+from fastapi import FastAPI, Response
+
+app = FastAPI()
+
+
+@app.get("/headers-and-object/")
+def get_headers(response: Response):
+    response.headers["X-Cat-Dog"] = "alone in the world"
+    return {"message": "Hello World"}