Enable GitLab multiline alerts

[digitalmoksha]

When the extensions alerts and multiline-block-quotes are enabled, then we now recognize GitLab style multiline alerts. For example

>>> [!note]
Something of interest.

And another thing...
>>>

will behave the same as

> [!note]
> Something of interest.
>
> And another thing...

This makes it easier to make an alert out of multiple paragraphs and blocks, in the same fashion as GitLab multiline block quotes

[github-actions]

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
./bench.sh ./comrak-0cda031	318.4 ± 2.4	315.6	324.4	2.92 ± 0.03
./bench.sh ./comrak-main	319.3 ± 4.5	315.4	335.2	2.93 ± 0.05
./bench.sh ./pulldown-cmark	109.1 ± 1.0	107.9	111.2	1.00
./bench.sh ./cmark-gfm	115.0 ± 1.7	112.2	117.7	1.05 ± 0.02
./bench.sh ./markdown-it	480.0 ± 4.3	475.2	490.8	4.40 ± 0.06

Run on Mon Jan 20 21:31:57 UTC 2025

[kivikakk]

Looking good! Have run fuzzing for a bit and will continue to do so, but I'm happy if you're happy. :)

[digitalmoksha]

Yeah I feel good about. Also ran fuzzing for a couple hours 👍

So I'll merge. Maybe we can cut a release whenever you have some time.

[charlottia]

Will make one tonight or tomorrow! :)

[charlottia]

Done! https://github.com/kivikakk/comrak/releases/tag/v0.34.0

[digitalmoksha]

Thanks! 🙇‍♂️