Improve error message in metadata parse
Improve error message in metadata parse

Fixes #3696

anthonyfok/hugo,fedelibre/hugo,anthonyfok/hugo,fedelibre/hugo,mdhender/hugo,gohugoio/hugo,mdhender/hugo,mdhender/hugo,gohugoio/hugo,mdhender/hugo,fedelibre/hugo,gohugoio/hugo,anthonyfok/hugo,fedelibre/hugo