Document how tracker detection is indicated in Query Log

### Prerequisites

- [x] I have checked the [Wiki](https://github.com/AdguardTeam/AdGuardHome/wiki) and [Discussions](https://github.com/AdguardTeam/AdGuardHome/discussions) and found no answer

- [x] I have searched other issues and found no duplicates

- [x] I want to request a feature or enhancement and not ask a question

### The problem

这个绿眼睛和灰眼睛啥意思，也没有说明文档

### Proposed solution

给个说明文档

### Alternatives considered and additional information

_No response_