Possible features in `minimal` option, and a working example

Bug description

(This is my first feedback, so I want to start sharing that I find Quarto really awesome.)

In the documentation it is said that using the minimal option, When specifying minimal: true you can still selectively re-enable features you do want, for example:

---
title: "My Document"
format:
  html:
    minimal: true
    code-copy: true
---

But:

1. the example of code-copy: true does not work well as the button is created by a CSS class (class="code-copy-button") and not by a regular UTF-8 char (such as 📋): the button appears very small, without any char, and it's very difficult to understand this is a button and its usage
2. what features are we talking about? It would be great to know what features can be enabled.

Steps to reproduce

Create a new .qmd document and add the following YAML plus some code. Eg.

---
title: "My Document"
format:
  html:
    minimal: true
    code-copy: true
---

Just testing:
```{r}

# Some R code

#library(leaflet)
#leaflet() %>%
#  addTiles() %>%  # Add default OpenStreetMap map tiles
#  addMarkers(lng=174.768, lat=-36.852, popup="The birthplace of R")
```

Then render it.

Expected behavior

I would expect:

• to have an easy to read copy button
• to know what features can be enabled (and works)

Actual behavior

Your environment

Quarto 1.4.553
IDE: RStudio 2023.12.1 Build 402
OS: Garuda Linux (Arch based)

Quarto check output

Start with the minimal HTML documentation section linked in the issue and review the minimal: true and code-copy: true options. Reproduce the provided .qmd example, then trace how the code-copy-button styling and selectively enabled features are documented. Done means the copy control is readable and the documentation clearly lists supported features.