feat(markdown): Add tip, caution and important notecard types

[queengooborg]

Summary

This PR is a follow-up to #10168 that adds support for three notecard types introduced by the GFM noteblocks proposal that Yari does not currently support: tip, important and caution.

Copyright notice: new icons for these types have been created by splicing together elements from existing icons. The light bulb for the new tip icon was created in-house by a vector artist from my company, Gooborg Studios.

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Markdown used:

## MDN Style

> **Note:** Note!

> **Tip:** A helpful tip

> **Important:** Something important

> **Warning:** Be weary of this!

> **Caution:** Don't set this thing!

> **Callout:** Some call to action!

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## GFM Proposal Style

> [!NOTE]
> Note!

> [!TIP]
> A helpful tip

> [!IMPORTANT]
> Something important

> [!WARNING]
> Be weary of this!

> [!CAUTION]
> Don't set this thing!

> [!CALLOUT]
> Some call to action!