Provides the legacy richtext wrapper.
Place wagtail.contrib.legacy.richtext before wagtail in INSTALLED_APPS.
INSTALLED_APPS = [
    ...
    "wagtail.contrib.legacy.richtext",
    "wagtail",
    ...
]
 The {{ page.body|richtext }} template filter will now render:
<div class="rich-text">...</div>
    © 2014-present Torchbox Ltd and individual contributors.
All rights are reserved.
Licensed under the BSD License.
    https://docs.wagtail.org/en/stable/reference/contrib/legacy_richtext.html