AX: VoiceOver iOS and OSX not announcing legend hint with aria-describedby if first input has hint

• Component: Accessibility
• Status: NEW ---

[Nick Colley]

### Overview

> The hint text for the aria-describedby on the input type="checkbox" supersedes the hint text for the aria-describedby on the fieldset. So the user only gets one hint read to them when they jump to the input through the tab index – the one on the input, rather than the legend.

1. Navigate to https://output.jsbin.com/juyaquq
2. Tab to first input

#### Minimal test case

```html
<fieldset aria-describedby="confirm-nationality-hint">
    <legend>
        What is your nationality?
    </legend>
    <span id="confirm-nationality-hint">
      Select all options that are relevant to you.
    </span>
    <br>
    <input id="confirm-nationality" name="confirm-nationality" type="checkbox" value="british-nationality" aria-describedby="confirm-nationality-item-hint">
    <label for="confirm-nationality">British</label>
    <span id="confirm-nationality-item-hint" class="govuk-hint govuk-checkboxes__hint">
      including English, Scottish, Welsh and Northern Irish
    </span>
    <br>
    <input name="confirm-nationality" type="checkbox" value="irish-nationality" aria-describedby="confirm-nationality-2-item-hint">
    <label class="govuk-label govuk-checkboxes__label" for="confirm-nationality-2">Irish</label>
    <span id="confirm-nationality-2-item-hint" class="govuk-hint govuk-checkboxes__hint">
      including from Northern Ireland
    </span>
    <br>
    <input id="confirm-nationality-3" name="confirm-nationality" type="checkbox" value="other-country-nationality" data-aria-controls="conditional-confirm-nationality-3">
    <label for="confirm-nationality-3">Citizen of a different country</label>
</fieldset>
```

JSBIN: https://output.jsbin.com/juyaquq

NVDA Version: 2019.2.1
Chrome version: 79.0.3945.130
Firefox version: 72.0.2

### Expected result

The legend is announced, followed by the legend hint, then the input and finally the input hint.

### Actual result

The legend is announced, then the input and finally the input hint.

[Radar WebKit Bug Importer]

<rdar://problem/59666537>

[Nick Colley]

Note the comments about NVDA, Chrome and Firefox can be ignored, this is also a problem there as VoiceOver.