[Appendix] `number-sections: true` also number the custom appendix

[cderv]

About https://quarto.org/docs/authoring/appendices.html#custom-appendix-sections

---
title: Test
format: 
  html:
    toc: true
    appendix-style: default
    number-sections: true
---

# Executive Summary {-}

{{< lipsum 1 >}}

# Introduction

## Text

{{< lipsum 1 >}}

Let's add a footnote^[that would be in same place as appendix]

## Subtitle

{{< lipsum 1 >}}

# Appendix {.appendix}

{{< lipsum 1 >}}

## Appendix Subtitle {.appendix}

{{< lipsum 1 >}}

The other part of the appendix is not

[cderv]

Related also to

• 10419