False negative on wcag/h30

Provide a broad description of the bug.

Reduced test-case

This code is outputting an error wcag/h30

<a alt="close left sidebar" class="btn btn-danger cursor_pointer close" data-action="close" data-side="left">
  <span alt="close left sidebar"></span>
</a>

I have the alt attribute on both the a element and span element, but still the error is being thrown

Configuration

const htmlvalidate = new HTMLValidate({
  extends: ['html-validate:recommended'],
  rules: {
    'no-trailing-whitespace': 'off',
    'attr-case': 'off',
    'long-title': 'off'
  }
})

Expected result

I'd expect no error since alt is provided on a element

Actual result

  {
    ruleId: 'WCAG/H30',
    severity: 2,
    message: 'Anchor link must have a text describing its purpose',
    offset: 6267,
    line: 108,
    column: 22,
    size: 1,
    selector: 'html > body > main > div:nth-child(1) > div:nth-child(1) > div > a',
    context: undefined
  }

Version

• html-validate: 2.16.0