Redcarpet::Render::StripDown does not remove the specified language in quote blocks

[opensourceame]

When stripping down Markdown, the language for a quote block is not removed in the stripped text, as per this example:

text = <<~END
```json
{"a": 1}
END

puts  Redcarpet::Markdown.new(Redcarpet::Render::StripDown).render(text)

Expected result

{"a": 1}

Actual result

json
{"a": 1}