message: add config for preview mode
diff: "default": true,
  "markdownDescription": "Enable preview for completion."
  },
  + "latex-workshop.intellisense.preview.render": {
  + "type": "string",
  + "enum": [
  + "dataUrl",
  + "file"
  + ],
  + "enumDescriptions": [
  + "Use data URL in markdown",
  + "Use cached file in markdown"
  + ],
  + "default": "dataUrl",
  + "markdownDescription": "Render mode for completion preview."
  + },
  "latex-workshop.message.badbox.show": {
  "type": "boolean",
  "default": true,
  