Support GfM alert

[idleberg]

Github flavoured Markdown (GfM) has introduced syntax for alerts, which has been adopted widely ever since.

This is what it looks like on GitHub:

The same banner on the OpenVSX website:

In my opinion, these alerts serve the purpose of highlighting important information where necessary. It would be awesome if they could be supported on the OpenVSX website.

If found a plugin Markdown-It, but there are probably multiple to choose from: https://www.npmjs.com/package/@mdit/plugin-alert

[netomi]

makes sense, ftr: the VSC Marketplace also does not render GitHub flavored Markdown, see https://marketplace.visualstudio.com/items?itemName=idleberg.jxa