Add to docs limiter must be below the route annotation in order to work

[transfluxus]

This works

@router.get("/test")
@limiter.limit("2/minute")
async def test(
        request: Request
):
    return "hi"

but this doesnt

@limiter.limit("2/minute")
@router.get("/test")
async def test(
        request: Request
):
    return "hi"

That would be useful for beginners to know (if they havent used any ratelimiter module before)