Minor: Improve withTrim

[bogeeee]

Like, see comment in jsdoc in
function withTrim in ServerSession.ts

---

This repo is using Opire - what does it mean? 👇

💸Everyone can add rewards for this issue commenting /reward 100 (replace 100 with the amount)
💪 If someone starts working on this issue to earn the rewards, they can comment /try to let everyone know!
🙌 And when they open the PR, they can comment /claim #8 either in the PR description or in a PR's comment

👀 Also, everyone can tip any user commenting /tip 20 @bogeeee (replace 20 with the amount, and @bogeeee with the user to tip)

If you want to learn more, go to our documentation