feat: add support for yaml [props] props syntax

[farnabaz]

There two syntaxes are same, and second one will be promoted and used by default, because it renderes good in all markdown renderes

frontmatter style

::home-hero
---
primary:
  text: 38K+ GitHub stars
  url: https://github.com/nuxt/nuxt.js
---
::

::home-hero

primary:
text: 38K+ GitHub stars
url: https://github.com/nuxt/nuxt.js

::

codeblock style

::home-hero
```yaml
primary:
  text: 38K+ GitHub stars
  url: https://github.com/nuxt/nuxt.js
```
::

::home-hero

primary:
  text: 38K+ GitHub stars
  url: https://github.com/nuxt/nuxt.js

::

[pkg-pr-new]

npm i https://pkg.pr.new/@comark/markdown-it@28

commit: db9d9f1