[Bug]: SmartyPants replaces `--` into an em-dash in <TerminalBlock>

[smikitky]

Summary

In https://react.dev/learn/typescript#adding-typescript-to-an-existing-react-project :

As you can see, -- has been converted to — (a non-ASCII em-dash). This happens during the site build step, so when someone copies this and pastes it into a terminal, they get an error.

The root cause is this file:

https://github.com/reactjs/react.dev/blob/b440d6698f6e21d56a78b10f625bd23191183588/plugins/remark-smartypants.js

It applies SmartyPants to all text AST nodes in Markdown. Since <TerminalBlock> is implemented using only simple <div>s and the plugin does not skip contents aside from <style> and <script>, the plugin converts --save-dev to —save-dev in <TerminalBlock>.

I think the fix would involve two steps:

1. Use <pre> or <code> appropriately to render the contents of <TerminalBlock>
2. In the plugin above, skip applying SmartyPants not only when the parent tag is <script>/<styule> but also when it's <code> or <pre>

[smikitky]

I found that other pages avoid this problem in a little hacky manner.

In build-a-react-app-from-scratch.md:

react.dev/src/content/learn/build-a-react-app-from-scratch.md

Lines 36 to 38 in b440d66

	<TerminalBlock>
	{`npm create vite@latest my-app -- --template react-ts`}
	</TerminalBlock>

This way, MDX treats the code not as a plain MD text node but as a React-ish embedded text expression, causing the SmartyPants plugin to skip it. This may not be very clean, but works.