Update a11y.js updates

[mgifford]

The A11y community suggested a few other commonly used classes.

Just adding to the list of known classes.

[github-actions]

https://almanac.httparchive.org/en/2022/

WPT result details

Changed custom metrics values:

{
  "_a11y": {
    "tables": {
      "total": 0,
      "total_with_caption": 0,
      "total_with_presentational": 0,
      "total_with_figcaption": 0
    },
    "file_extension_alts": {
      "total_elements_with_alt": 5,
      "total_elements_with_non_empty_alt": 0,
      "total_with_file_extension": 0,
      "file_extensions": {}
    },
    "title_and_alt": {
      "total_alt": 5,
      "total_title": 5,
      "total_both": 0,
      "total_alt_same_as_title": 0
    },
    "th_with_scope_attribute": {
      "total_th": 0,
      "total_with_scope": 0,
      "scopes": {}
    },
    "td_with_headers_attribute": {
      "total_tds": 0,
      "total_with_headers": 0
    },
    "total_anchors_with_role_button": 0,
    "total_role_tab_with_selected_and_controls": 0,
    "placeholder_but_no_label": {
      "total_placeholder": 4,
      "total_no_label": 0
    },
    "divs_or_spans_as_button_or_link": {
      "total_role_button": 0,
      "total_role_link": 0,
      "total_either": 0
    },
    "screen_reader_classes": false,
    "form_control_a11y_tree": {
      "__error": {
        "stack": "TypeError: Cannot read properties of undefined (reading 'value')\n    at addControlToStats (<anonymous>:202:28)\n    at <anonymous>:246:1\n    at captureAndLogError (<anonymous>:30:8)\n    at wptCustomMetric (<anonymous>:195:25)\n    at <anonymous>:318:7",
        "message": "Cannot read properties of undefined (reading 'value')"
      }
    },
    "fieldset_radio_checkbox": {
      "total_radio": 0,
      "total_checkbox": 0,
      "total_radio_in_fieldset": 0,
      "total_checkbox_in_fieldset": 0,
      "fieldsets": []
    },
    "required_form_controls": []
  }
}