[flake8-async] Make ASYNC105 example error out-of-the-box

[MeGaGiGaGon]

Summary

Part of #18972

This PR makes trio-sync-call (ASYNC105)'s example error out-of-the-box

Old example

async def double_sleep(x):
    trio.sleep(2 * x)

New example

import trio


async def double_sleep(x):
    trio.sleep(2 * x)

Test Plan

N/A, no functionality/tests affected

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.