pandoc HTML chapter numbering is off by one due to preface being treated like a chapter #28
Description
The HTML generated by pandoc has hardcoded chapter numbers that are incorrect:
<li><a href="#preface"><span class="toc-section-number">1</span>
--
| Preface</a></li>
| <li><a href="#introduction"><span class="toc-section-number">2</span>
| Introduction<span id="sec:introduction"
| label="sec:introduction"></span></a>
| <ul>
| <li><a href="#process-empathy"><span
| class="toc-section-number">2.1</span> Process Empathy<span
| id="sec:process-empathy" label="sec:process-empathy"></span></a></li>
| <li><a href="#what-is-bureaucracy"><span
| class="toc-section-number">2.2</span> What is Bureaucracy?<span
| id="sec:define-bureaucracy"
| label="sec:define-bureaucracy"></span></a></li>
<li><a href="[#preface](https://github.com/processempathy/bureaucracy-guidebook/issues/new#preface)"><span class="toc-section-number">1</span>
Preface</a></li>
<li><a href="[#introduction](https://github.com/processempathy/bureaucracy-guidebook/issues/new#introduction)"><span class="toc-section-number">2</span>
Introduction<span id="sec:introduction"
label="sec:introduction"></span></a>
<ul>
<li><a href="[#process-empathy](https://github.com/processempathy/bureaucracy-guidebook/issues/new#process-empathy)"><span
class="toc-section-number">2.1</span> Process Empathy<span
id="sec:process-empathy" label="sec:process-empathy"></span></a></li>
<li><a href="[#what-is-bureaucracy](https://github.com/processempathy/bureaucracy-guidebook/issues/new#what-is-bureaucracy)"><span
class="toc-section-number">2.2</span> What is Bureaucracy?<span
id="sec:define-bureaucracy"
label="sec:define-bureaucracy"></span></a></li>As a result, the HTML and the PDF do not have same chapter numbers.