fixed typo for enabled colored diffs in code blocks.

[madogiwa0124]

Fixed typo in comment for code block diff for minimum virtual DOM.

export interface VNode<HostNode = RendererNode> {
 type: VNodeTypes;
 props: VNodeProps | null;
 children: VNodeNormalizedChildren;
 el: HostNode | undefined; // [!code++]
}

https://ubugeeei.github.io/chibivue/10-minimum-example/040-minimum-virtual-dom.html#%E5%AE%9F%E9%9A%9B%E3%81%AB%E5%AE%9F%E8%A3%85%E3%81%97%E3%81%A6%E3%81%BF%E3%82%8B

Colored Diffs in Code Blocks Adding the // [!code --] or // [!code ++] comments on a line will create a diff of that line, while keeping the colors of the codeblock. https://vitepress.dev/guide/markdown#colored-diffs-in-code-blocks

[ubugeeei]

Thank you ♥️