Small suggestion: Add /ot to the list of synonyms for /ask and /btw

### Describe the feature or problem you'd like to solve

The first time I wished the feature existed, I tried typing /ot (for off-topic). That was my first instinct, and others might have the same.

### Proposed solution

What the title says: Add /ot to the list of synonyms for /ask and /btw.

Off-topic has a good correlation with what the feature is about. I guess it depends on their mental model. I just think it can be more intuitive for some people to type /ot than /ask or /btw. Unless you are reserving /ot for something else, I think it's an easy win.

### Example prompts or workflows

/ot what is the command to block inbound traffic based on ip address?

### Additional context

_No response_

まず、CLI で /ask と /btw のコマンド定義または同義語リストを見つけます。/ot をエイリアスとして追加し、issue の例のような /ot プロンプトが /ask および /btw と同じワークフローに従うことを確認します。

索引モデルが issue の本文から書いたものです。