Build error or warning when using non-supported custom container

[o-l-a-v]

Is your feature request related to a problem? Please describe.

Build does not error or warn when a user wrongfully uses a non-supported custom container ( https://vitepress.dev/guide/markdown#custom-containers ), like ::: NOTE, ref:

• Add note to custom containers #4427

Current behavior is just to build with no warning or error, which makes it harder to catch issues like this:

Describe the solution you'd like

Error or warn when using a non-supported custom container.

Describe alternatives you've considered

No response

Additional context

No response

Validations

• Follow our Code of Conduct
• Read the docs.
• Read the Contributing Guidelines.
• Check that there isn't already an issue that asks for the same feature to avoid creating a duplicate.

[o-l-a-v]

One more example that could've been caught during build: jdx/mise#3876

Sh code block used:

:::sh
<code>
:::

Should've been:

```sh
<code>
```

[brc-dd]

As a workaround, you can add something like this:

import { defineConfig } from 'vitepress';
import mditContainer from 'markdown-it-container';

export default defineConfig({
  markdown: {
    config(md) {
      mditContainer(md, '_', {
        validate(params) {
          params = params.trim();
          if (params)
            console.warn(
              `\n\x1b[33mUnknown markdown container - ${params}\x1b[0m`
            );
          return false;
        },
      });
    },
  },
});

It won't show you the file name / line number though.

https://stackblitz.com/edit/vite-yhmisdwk?file=docs/.vitepress/config.ts