在WagTail中，如何显示嵌入在富文本中的文档链接的完整文档url？

from wagtail.core import blocks
from wagtail.documents.blocks import DocumentChooserBlock

class MyRichTextBlock(blocks.StructBlock):
    content = blocks.RichTextBlock(features=['bold', 'italic'])
    document = DocumentChooserBlock()

    class Meta:
        icon = 'doc-full'
        template = 'myapp/blocks/my_rich_text_block.html'

{% load wagtailcore_tags %}

<div class="richtext">
    {{ value.content|richtext }}
</div>
{% if value.document %}
    <a href="{{ value.document.url }}">{{ value.document.title }}</a>
{% endif %}

from django.db import models
from wagtail.core.models import Page
from wagtail.core.fields import StreamField
from myapp.blocks import MyRichTextBlock

class MyPage(Page):
    body = StreamField([
        ('rich_text', MyRichTextBlock()),
    ], blank=True)