fix: misc plugin fixes

[Princesseuh]

to merge with #63 really

[codspeed-hq]

Merging this PR will not alter performance

✅ 19 untouched benchmarks
🆕 5 new benchmarks
⏩ 8 skipped benchmarks¹

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
🆕	HAST replaceNode keep-children (links)	N/A	5.1 ms	N/A
🆕	MDAST build-subtree (paragraphs)	N/A	5.2 ms	N/A
🆕	MDAST replaceNode keep-children (links)	N/A	2.6 ms	N/A
🆕	parse_markdown	N/A	866.5 µs	N/A
🆕	parse_mdx	N/A	99.2 µs	N/A

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_{Comparing fix/plugin-things (3391f84) with main (42835bc)}

Footnotes

1. 8 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩