Add email in package description

Fix #531

Author: condy0919

Diff for: rust-mode.el

@@ -1,7 +1,7 @@
 ;;; rust-mode.el --- A major-mode for editing Rust source code -*-lexical-binding: t-*-
 
 ;; Version: 1.0.5
-;; Author: Mozilla
+;; Author: Mozilla <[email protected]>
 ;; Url: https://github.com/rust-lang/rust-mode
 ;; Keywords: languages
 ;; Package-Requires: ((emacs "25.1"))