🔥 Remove Python 3.9 specific files, no longer needed after updating translations (#14931)

docs_src/middleware/tutorial001_py39.py

@@ -1,14 +0,0 @@
-import time
-
-from fastapi import FastAPI, Request
-
-app = FastAPI()
-
-
-@app.middleware("http")
-async def add_process_time_header(request: Request, call_next):
-    start_time = time.perf_counter()
-    response = await call_next(request)
-    process_time = time.perf_counter() - start_time
-    response.headers["X-Process-Time"] = str(process_time)
-    return response