fix: strikethrough doesn't render with underline

[Saif-Alhaider]

Fix: Strikethrough Links Not Rendering Properly

This PR fixes the issue where strikethrough links (e.g., ~[This is a link](https://example.com)~) were not displaying the strikethrough effect. Now, both the link styling and strikethrough are correctly applied.

Closes #299

[mikepenz]

Thank you very much for the PR, I'll have to look more into it. What worries me a bit is that we specifically have to look out for strikethrough in that case, and are not depending on the general annotated string builder which would handle more than just strikethrough.

test italic bold strikethrough italic test

[Saif-Alhaider]

Thank you for the feedback, I understand the concern about handling only strikethrough and not relying on the general AnnotatedString Builder. I'll look into finding a solution to ensure we handle multiple text styles (like italic, bold, and strikethrough) in a more integrated way. I'll keep you updated on my progress.

[mikepenz]

Strictly speaking all the spans should already be applied at that point 🤔 I suppose the way compose handles links inside an annotated string overrides all the other spans that apply to this section already.

I also just realized that my example was the inverse :D where the style was within the link and not from the outside.

Generally we might need to do something like this:
https://github.com/mikepenz/multiplatform-markdown-renderer/blob/develop/multiplatform-markdown-renderer/src/commonMain/kotlin/com/mikepenz/markdown/compose/extendedspans/SquigglyUnderlineSpanPainter.kt#L115-L119

where we get the spans for the range of the string and apply the similar "special" text stylings like underline, bold, italic, strikethrough, ...

[mikepenz]

Testing with:

[test *italic* **bold** ~strikethrough~ _italic_ test](https://mikepenz.dev)
*[italic](https://mikepenz.dev)*
**[bold](https://mikepenz.dev)**
~[strikethrough](https://mikepenz.dev)~
_[italic](https://mikepenz.dev)_

It seems like only strikethrough is not respected

[mikepenz]

Looking more into this. parent wouldn't work unfortunately. as the link style may be surrounding nodes.

I wonder if the problem should be mostly considered to be they way TextLinkStyles work in annotated strings :/

[mikepenz]

as we are in that stage still using a AnnotatedString.Builder we also can't get the applied spans yet. so that ain't work either