[Bug] Attribute marked private recipes not private in json dump

[nefrob]

Ex. given the following justfile

[private]
my-private-recipe:
  echo "private"

running just --dump --dump-format json yields

  "recipes": {
    "my-private-recipe": {
      "attributes": [
        "private"
      ],
      "body": [
        [
          "echo \"private\""
        ]
      ],
      "dependencies": [],
      "doc": null,
      "name": "my-private-recipe",
      "namepath": "my-private-recipe",
      "parameters": [],
      "priors": 0,
      "private": false,
      "quiet": false,
      "shebang": false
    }
  }

while just --list yields nothing.

[casey]

Good catch! Fixed in #2415.