docs: remove Python 3.9 example for tutorial005

docs_src/body/tutorial005_py39.py

@@ -1,13 +0,0 @@
-from fastapi import FastAPI
-from pydantic import BaseModel
-
-app = FastAPI()
-
-
-class Item(BaseModel):
-    description: str | None
-
-
-@app.post("/items/")
-async def create_item(item: Item):
-    return item