Support formatting of alert boxes

[PrajwolAmatya]

Description

This PR adds the functionality to support the formatting of alert boxes in the presentation slides.

Screenshot

Input markdown content

> [!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.

Rendered output:

Related WP

https://community.openproject.org/projects/revealjs/work_packages/60582/activity

[individual-it]

I think this regex will NOT catch these inputs, which GitHub is happily working with:

multi line

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

multiple spaces after >

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

But it will catch these inputs, that GitHub does not use as alert boxes:

invalid type

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

empty line between type and text

> [!CAUTION]

> Advises about risks or negative outcomes of certain actions.

double >

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

missing new line

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

I think we need tests here to make sure all those and other cases work correctly

[individual-it]

what about ?

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

Is that a valid input? At least for GitHub it is. But I think the replace will not catch it

[PrajwolAmatya]

Caution

> Advises about risks or negative outcomes of certain actions.

It looks like github only removes > if only it is in the beginning of the line.

[individual-it]

what if alertIcons does not have an item with the type?
You could have a check here, then the regex does not need to contain all types. Or you construct a complicated regex dynamically.

[PrajwolAmatya]

In that case, i have updated the code and it will be a normal block quote.