Nested fenced divs parsing bug

[kazalex]

Input:

:::: {.a}

- ::: {.b}
  text
  :::
  ::: {.c}
  text
  :::

::::

Output:

<div class="a">
<ul>
<li>::: {.b} text</li>
</ul>
</div>
<div class="c">
<p>text</p>
</div>
<p>::::</p>

1.First nested div (class .b) is not recognized
2.Second nested div (class .c) is recognized but placed outside of ul and li

[jgm]

Simpler case:

::: {.a}
- ::: {.b}
  :::
:::

[jgm]

Note that this version works okay:

% pandoc -t native
<div class="a">
- <div class="b">
  </div>
</div>
[Div ("",["a"],[])
 [BulletList
  [[Div ("",["b"],[])
    []]]]]