Fix quoted text rendering (mixing '>' and ```quote ?)

[neiljp]

The following quoted text renders incorrectly (see 'quote zt FAIL' topic on #test here on chat.zulip.org).

@sumanthvrao Perhaps a followup PR for you at some point?

The text is below this line, but due to markdown-within-markdown limits, it doesn't appear to work that well.

---

```quote
>foo

bar

>foo2

bar2

baz

end

[sumanthvrao]

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