[Bug]: Doc right aside do not contain the title of document fragments

[chenjiahan]

Version

System:
    OS: macOS 13.4.1
    CPU: (10) arm64 Apple M1 Pro
    Memory: 5.36 GB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Browsers:
    Chrome: 114.0.5735.198
    Safari: 16.5.1
  npmPackages:
    @modern-js/doc-tools: workspace:* => 2.26.0 
    @modern-js/tsconfig: workspace:* => 2.26.0

Details

The right aside bar do not contain the title of document fragments.

For example, The "CLI Tool" chapter is imported as a Component:

import CliToolVue from '@zh/shared/cliToolVue.md';

<CliToolVue />

And the generated aside bar do not contain "CLI Tool":

Reproduce link

https://github.com/web-infra-dev/modern.js

Reproduce Steps

1. cd packages/document/builder
2. pnpm run dev