Pasting markdown footnotes results in nothing being pasted

Given markdown footnotes:

```
[^1]: https://hey.com
[^2]: https://pagecord.com
[^3]: https://basecamp.com
```

Copy these as plain text from VS Code, then pasting using Cmd+V on Mac into Lexxy works:

```

[^1]: https://hey.com

[^2]: https://pagecord.com

[^3]: https://basecamp.com

However if you paste using Cmd+Shift+V (paste as plain text) then _nothing_ is pasted. Lexxy gobbles it up.

Reproduce the issue in Lexxy on macOS by copying the shown markdown footnotes from VS Code and using Cmd+Shift+V. Trace the plain-text paste handling and consider the work done when those footnote lines are inserted instead of being swallowed; verify that regular Cmd+V still works.

Written by the indexing model from the issue text.