404 for some snippets, but next ones work

There are some queries where the [first one](https://cht.sh/rust/flush+stdout) works, [second one](https://cht.sh/rust/flush+stdout/1) broken, [third one](https://cht.sh/rust/flush+stdout/2) works again :confused:

```
$ http https://cht.sh/rust/flush+stdout/1
HTTP/1.1 200 OK
Connection: keep-alive
Content-Length: 1611
Content-Type: text/plain; charset=utf-8
Date: Fri, 03 Mar 2023 15:57:31 GMT
Server: nginx/1.13.12
Strict-Transport-Security: max-age=63072000; includeSubdomains
X-Content-Type-Options: nosniff
X-Frame-Options: DENY

/*
* 404 NOT FOUND
*
* Unknown cheat sheet. Please try to reformulate your query.
* Query format:
*/

/LANG/QUESTION

// Examples:
```

Reproduce the failure with the three linked rust/flush+stdout URLs and the shown http command, then trace the request handling for numbered snippet paths. Compare the responses for /1 and /2 and identify why an existing snippet returns the 404 template. Done means the affected numbered snippets return their expected content consistently.

Written by the indexing model from the issue text.