doc(ford): fix author email metadata tag

Author: rouson

API-doc-FORD-file.md

@@ -26,7 +26,7 @@ license: by-sa
 author: Paul N. Swarztrauber &
         fortran-lang/fftpack contributors
 author_pic: https://fortran-lang.org/assets/img/fortran_logo_512x512.png
-author_email: [email protected]
+email: [email protected]
 github: https://github.com/fortran-lang
 twitter: https://twitter.com/fortranlang
 website: https://fortran-lang.org