Label on import this cell in docs is not properly set

[agoose77]

This is a small issue tracking an incorrect label in the docs:

For some reason, the #| label:zen is not properly setting the label. Instead, each char in label:zen is being taken as an array of items in data. I suspect the lack of whitespace between key and value is at fault.

❯ curl -s https://mystmd.org/guide/interactive-notebooks.json | jq .mdast.children[10].data
{
  "0": "l",
  "1": "a",
  "2": "b",
  "3": "e",
  "4": "l",
  "5": ":",
  "6": "z",
  "7": "e",
  "8": "n",
  "editable": true,
  "slideshow": {
    "slide_type": ""
  },
  "tags": []
}