Consider this markdown:

[link]: destination "
          text          "

[link]

It's another place where pulldown-cmark diverges from most other implementations. The dingus thinks there's ten spaces after the word "text", but no spaces before it. markdown-it, commonmark-hs, and GFM all seem to agree.

In other words, they all make this HTML:

<p><a href="destination" title="
text          ">link</a></p>

The exception is goldmark. It does this:

<p><a href="destination" title="
          text          ">link</a></p>

pulldown-cmark does this:

<p><a href="destination" title="
      text          ">link</a></p>