add newline between comment and package

[ethanmdavidson]

When jade.go begins with

// Code generated by "jade.go"; DO NOT EDIT.
package jade

staticcheck fails with package comment should be of the form "Package jade ..." (ST1000).

The other generated go files don't have this problem because they put a newline between the comment and the package declaration.

Adding a newline to jade.go as well will cause staticcheck to stop complaining.