As of T4119:
- some blockquotes can have headers; and
- blockquotes can nest.
These could probably use some refinement, particularly in the header case.
Write a header with `>>!`. Quote with `>`. Multiple `>` nests the quote. Here are some examples:
>>! replying author wrote:
>>>! original author wrote:
>> i have an opinion
> your opinion is bad, and you are bad
> beep
>> boop
>>> bip
>>>> blip