[CommonMark] false positive for list.loose caused by trailing newline with whitespaces

[ikatyang]

Subject of the issue

commonmark: true

- 123
  

(Note that there're two whitespaces in the last line.)

Steps to reproduce

astexplorer

Expected behaviour

Same as CommonMark playground:

{
  "type": "root",
  "children": [
    {
      "type": "list",
      "ordered": false,
      "start": null,
      "loose": false,
      "children": [
        {
          "type": "listItem",
          "loose": false,
          "checked": null,
          "children": [
            {
              "type": "paragraph",
              "children": [{ "type": "text", "value": "123" }]
            }
          ]
        }
      ]
    }
  ]
}

Actual behaviour

 {
   "type": "root",
   "children": [
     {
       "type": "list",
       "ordered": false,
       "start": null,
-      "loose": false,
+      "loose": true,
       "children": [
         {
           "type": "listItem",
-          "loose": false,
+          "loose": true,
           "checked": null,
           "children": [
             {
               "type": "paragraph",
               "children": [{ "type": "text", "value": "123" }]
             }
           ]
         }
       ]
     }
   ]
 }

Original post: prettier/prettier#5021

[wooorm]

Probably related to GH-349!