Is your feature request related to a problem? Please describe.
For the purposes of meeting accessibility requirements, when an item has instructional text, the content is visibly associated to the on-screen field, but not so when a screen reader reads the content. The screen reader user has to tab to invoke the instructional text.

Example item content

"item": [
    {
        "extension": [
            {
                "url": "http://hl7.org/fhir/StructureDefinition/questionnaire-displayCategory",
                "valueCodeableConcept": {
                    "coding": [
                        {
                            "system": "http://hl7.org/fhir/questionnaire-display-category",
                            "code": "instructions"
                        }
                    ]
                }
            }
        ],
       "linkId": "1-Background-Chap1Tel-Instructions",
       "text": "Please enter a valid Australian phone number",
       "type": "display"
    }
]

Describe the solution you'd like
From an accessibility perspective, it is preferrable to have the instructional text programmatically associated with its parent field, so that the content is read out immediately when the field receives focus (rather than having it need a tab key press). Accessibility experts suggest the use of the aria-describedby attribute to associate hint text with the input field.

Describe alternatives you've considered
None

Additional context
None