fix(i18n): make sure to use correct fileData for manual localization (#975)

Signed-off-by: Aaron <29749331+aarnphm@users.noreply.github.com>

quartz/plugins/transformers/frontmatter.ts

@@ -90,6 +90,7 @@ declare module "vfile" {
         description: string
         publish: boolean
         draft: boolean
+        lang: string
         enableToc: string
         cssclasses: string[]
       }>