[Bug]: markdown headings in MDX are broken (no html anchors)

[Powerplex]

Describe the bug

Using Storybook with @storybook/react-vite with @storybook/addon-essentials, I can't seem to get anchors to work in MDX files.

Hovering them simply does not display the icon, and my links pointing to anchors does not work. I see no ids on the headings when I inspect the HTML.

This is a big issue for me, developers should be able to share urls to a specific section of a page.

To Reproduce

Here is a file where anchors are not working: https://github.com/Powerplex/vite-storybook-poc/blob/master/src/stories/docs/WritingStories.mdx

You can clone the repo and use this branch to reproduce: 
- `npm i`
- `npm run start` (Will open storybook in your browser)
- Open the `Contributing/Writing Stories` Docs from the interface.

I think this previous fix was supposed to take care of it but I still have the bug

System

Environment Info:

  System:
    OS: macOS 12.1
    CPU: (10) arm64 Apple M1 Pro
  Binaries:
    Node: 18.11.0 - ~/.nvm/versions/node/v18.11.0/bin/node
    npm: 8.19.2 - ~/.nvm/versions/node/v18.11.0/bin/npm
  Browsers:
    Chrome: 108.0.5359.124
    Firefox: 107.0
    Safari: 15.2
  npmPackages:
    @storybook/addon-essentials: ^7.0.0-beta.19 => 7.0.0-beta.19
    @storybook/addon-interactions: ^7.0.0-beta.19 => 7.0.0-beta.19
    @storybook/addon-links: ^7.0.0-beta.19 => 7.0.0-beta.19
    @storybook/blocks: ^7.0.0-beta.19 => 7.0.0-beta.19
    @storybook/react: ^7.0.0-beta.19 => 7.0.0-beta.19
    @storybook/react-vite: ^7.0.0-beta.19 => 7.0.0-beta.19
    @storybook/testing-library: ^0.0.14-next.1 => 0.0.14-next.1

[Paul-Hebert]

FWIW I'm also seeing this when using 6.5.13 (Preact)

    "@storybook/addon-actions": "^6.5.13",
    "@storybook/addon-essentials": "^6.5.13",
    "@storybook/addon-interactions": "^6.5.13",
    "@storybook/addon-links": "^6.5.13",
    "@storybook/builder-vite": "^0.2.5",
    "@storybook/preact": "^6.5.13",
    "@storybook/testing-library": "^0.0.13",

[Rockstar79]

I'm running into this issue as well.

"@storybook/addon-essentials": "^6.5.15",
"@storybook/builder-vite": "^0.3.0",
"@storybook/core-common": "^6.5.15",
"@storybook/core-server": "^6.5.15",
"@storybook/web-components": "^6.5.15",

[shilman]

If anybody is still seeing this on 7.0, do you a have a reproduction repo you can share? Thank you! 🙏

[shilman]

Ooh-la-la!! I just released https://github.com/storybookjs/storybook/releases/tag/v7.0.0-rc.10 containing PR #21796 that references this issue. Upgrade today to the @next NPM tag to try it out!

npx sb@next upgrade --prerelease

[Powerplex]

@shilman it works like a charm :D Thank you very much.