fix: correctly parse falsy js as title (#900)

Eiko Wagenknecht

2024-02-19 b6cf3df84f452c22ac9ddaf452b0ecbe0828086f

 quartz/plugins/index.ts

@@ -30,5 +30,6 @@
  interface DataMap {
    slug: FullSlug
    filePath: FilePath
    relativePath: FilePath
  }
}