### Bug description


## Here is a minimal example.

````
---
title: "Untitled"
format:
  html:
    include-in-header:
      - header.html
---

## Math

$$
\bm{x} + x + \cancel{\text{///}}
$$
````

## The content of `header.html` as follow

```js
<script type="text/x-mathjax-config">
    MathJax.Hub.Config({
      TeX: {
        Macros: {
          bm: ["{\\boldsymbol #1}",1],
        },
        extensions: ["cancel.js"]
      }
    });
</script>
```

## The output is

![](https://user-images.githubusercontent.com/12031874/222962318-9eda0493-ae02-4b3a-8c64-6cc63583e3c3.png)

That means user-defined TeX macros doesn't work.

## Quarto and RStudio IDE

I use Quarto 1.3.242

RStudio 2023.03.0+382 "Cherry Blossom" Release (3a8b92eb66f0754a31f03c010b41496abc65fb70, 2023-03-01) for macOS
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) RStudio/2023.03.0+382 Chrome/108.0.5359.179 Electron/22.0.3 Safari/537.36



### Checklist

- [X] Please include a minimal, fully reproducible example in a single .qmd file? Please provide the whole file rather than the snippet you believe is causing the issue.
- [X] Please [format your issue](https://quarto.org/bug-reports.html#formatting-make-githubs-markdown-work-for-us) so it is easier for us to read the bug report.
- [X] Please document the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
- [X] Please document the operating system you're running. If on Linux, please provide the specific distribution.
2023-03-05T13:12:55Z
XiangyunHuang
bug
closed
Defining TeX macros in`include-in-header` does not work in HTML output
https://github.com/quarto-dev/quarto-cli/issues/4629