Function createAtomBlockMarkdownSpec

createAtomBlockMarkdownSpec(
    options: AtomBlockMarkdownSpecOptions,
): {
    markdownTokenizer: MarkdownTokenizer;
    parseMarkdown: (
        token: MarkdownToken,
        h: MarkdownParseHelpers,
    ) => MarkdownParseResult;
    renderMarkdown: (node: JSONContent) => string;
}
Creates a complete markdown spec for atomic block nodes using Pandoc syntax.

The generated spec handles:
- Parsing self-closing blocks with :::blockName {attributes}
- Extracting and parsing attributes
- Validating required attributes
- Rendering blocks back to markdown
Parameters
- options: AtomBlockMarkdownSpecOptions
  Configuration for the atomic block markdown spec
Returns {
    markdownTokenizer: MarkdownTokenizer;
    parseMarkdown: (
        token: MarkdownToken,
        h: MarkdownParseHelpers,
    ) => MarkdownParseResult;
    renderMarkdown: (node: JSONContent) => string;
}
Complete markdown specification object
Example
```
const youtubeSpec = createAtomBlockMarkdownSpec({
  nodeName: 'youtube',
  requiredAttributes: ['src'],
  defaultAttributes: { start: 0 },
  allowedAttributes: ['src', 'start', 'width', 'height'] // Only these get rendered to markdown
})

// Usage in extension:
export const Youtube = Node.create({
  // ... other config
  markdown: youtubeSpec
})
```
- Defined in node_modules/@tiptap/core/dist/index.d.ts:4528