message: Document new bibtex-format.sortBy type
diff: "items": {
  "type": "string"
  },
  - "markdownDescription": "An array of strings to sort by. Either a bibtex field name (title, author, year, etc.), or `\"year-desc\"` to sort by year in descending order, or `\"key\"` for the entry key. E.g. `[\"author\", \"year-desc\", \"title\"]`.",
  + "markdownDescription": "An array of strings to sort by. Either a bibtex field name (title, author, year, etc.), or `\"year-desc\"` to sort by year in descending order, or `\"key\"` for the entry key, or `\"type\"` for the entry type (article, book, misc, etc.). E.g. `[\"author\", \"year-desc\", \"title\"]`.",
  "default": [
  "key"
  ]
  