インクルードしてセクションにくくってくれて適宜`hr`で戻してくれるみたいなMarkdownプリプロセッサーが欲しい

bar.txt

# Bar

This paragraph comes from "bar".

buz.txt

# Buz

This paragraph comes from "buz".

foo.txt

# Foo

This paragraph comes from "foo".

<!-- inc bar.md -->

<!-- inc buz.md -->

This paragraph comes from "foo".

output.html

<h1>Foo</h1>

<p>This paragraph comes from "foo".</p>

<section>
  <h1>Bar</h1>

  <p>This paragraph comes from "bar".</p>
</section>

<section>
  <h1>Buz</h1>

  <p>This paragraph comes from "buz".</p>
</section>

<hr>

<p>This paragraph comes from "foo".</p>