Support GitHub-like alerts in MDX files

[terrymun]

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

There is no easy way of styling alert messages. All we have is to use the <blockquote> element to generate generic-looking alerts in MDX docs:

> **NOTE**: Useful information that users should know, even when skimming content.

> **TIP**: Helpful advice for doing things better or more easily.

> **IMPORTANT**: Key information users need to know to achieve their goal.

> **WARNING**: Urgent info that needs immediate user attention to avoid problems.

> **CAUTION**: Advises about risks or negative outcomes of certain actions.

Describe the solution you'd like

It would be nice that Storybook supports GitHub-like alerts out of the box in MDX, e.g. I can do something like this:

> [!NOTE]
> Useful information that users should know, even when skimming content.

> [!TIP]
> Helpful advice for doing things better or more easily.

> [!IMPORTANT]
> Key information users need to know to achieve their goal.

> [!WARNING]
> Urgent info that needs immediate user attention to avoid problems.

> [!CAUTION]
> Advises about risks or negative outcomes of certain actions.

Alternatively, create a new DocBlocks component that allows us to inject these into our MDX documentation, e.g.:

import { Alert } from '@storybook/addon-docs';

# Hello world!

<Alert type="note">
  Useful information that users should know, even when skimming content.
</Alert>

<Alert type="tip">
  Helpful advice for doing things better or more easily.
</Alert>

<Alert type="important">
  Key information users need to know to achieve their goal.
</Alert>

<Alert type="warning">
  Urgent info that needs immediate user attention to avoid problems.
</Alert>

<Alert type="caution">
  Advises about risks or negative outcomes of certain actions.
</Alert>

Describe alternatives you've considered

No response

Are you able to assist to bring the feature to reality?

yes, I can

Additional context

No response