Ensure required elements are present

Rule ID:: element-required-content
Category:: Content model
Standards:: HTML5

Some elements has requirements where certain child elements has to be present.

The requirements comes from the element metadata:

{
  "my-element": {
    "requiredContent": ["my-other-element"]
  }
}

Rule details

Examples of incorrect code for this rule:

<html>
    <head>
    </head>
</html>

error: <html> element must have <body> as content (element-required-content) at inline:1:2:
> 1 | <html>
    |  ^^^^
  2 |     <head>
  3 |     </head>
  4 | </html>


error: <head> element must have <title> as content (element-required-content) at inline:2:6:
  1 | <html>
> 2 |     <head>
    |      ^^^^
  3 |     </head>
  4 | </html>


2 errors found.

Examples of correct code for this rule:

<html>
    <head>
        <title>foo</title>
    </head>
    <body></body>
</html>