set text-decoration to none if no styles are provided when using the append property

[rishichawda]

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Description of changes

I found a bug where there's a trailing space at the end of the header when using the append property. This shows up as an underscore because of text decoration. I have put all the details in #26.

This PR is trying to patch this by setting it to none when no styles are passed and that seems to be fixing the issue. However, I admit I haven't worked with serious JS code for quite some time and I might be a little rusty. There's probably a better way to solve this.

[github-actions]

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• Initial checklist (todo)
• Description of changes

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### Initial checklist

* [ ] I read the support docs <!-- https://github.com/rehypejs/.github/blob/main/support.md -->
* [ ] I read the contributing guide <!-- https://github.com/rehypejs/.github/blob/main/contributing.md -->
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### Description of changes

TODO

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Thanks,
— bb

[wooorm]

You are adding styles for everyone, a breaking change, which probably not everyone wants.
Probably not the best solution for your problem?

[rishichawda]

@wooorm Yeah that's why I wrote in my PR description that there is probably a better way to solve this. I tried finding where the trailing space is coming from but I don't see it in output html.

[rishichawda]

I found out where the space was coming from #26 (comment)