Headertag Form Field
The headertag form field type provides a dropdown list of h1 to h6 as options.
- type (mandatory) must be headertag.
 - name (mandatory) is the unique name of the field.
 - label (mandatory) (translatable) is the field html label.
 - description (optional) (translatable) is the field description.
 - default (optional) (not translatable) is the default value.
 
Implemented by: libraries/src/Form/Field/HeadertagField.php
Example XML parameter definition
<field
        name="header_tag" 
        type="headertag"
        label="COM_MODULES_FIELD_HEADER_TAG_LABEL"
        description="COM_MODULES_FIELD_HEADER_TAG_DESC"
        default="h3"
/>