Jade模板出错：prolog中不允许使用字符“d”

Question

当我创建这个简单的Jade文档时：

doctype html
html
    head
        title welcome
    body hi, world

我在控制台中收到此错误消息：

/usr/bin/jade user_form.jade
/usr/bin/jade:user_form.jade:1:0:E: character "d" not allowed in prolog
/usr/bin/jade:user_form.jade:5:19:E: end of document in prolog
/usr/bin/jade:E: cannot find "user_form.dsl"; tried "user_form.dsl", "/usr/share/sgml/user_form.dsl"
/usr/bin/jade:E: specification document does not have the DSSSL architecture as a base architecture

Process finished with exit code 1

当我启动node.js应用程序时，此模板工作文件，那么为什么WebStorm会返回此错误消息？