sublime text3设置txt文件类型也能自动补充，自动完成
Preferences- settings user -Preferences.sublime-settings中设置自动触发：
"auto_complete_triggers":
[
{"selector": "text.html", "characters": "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.<"},
{"selector": "text.plain", "characters": "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.<"}
],
text.plain及为普通的txt文件类型
text.html为html文件
文件类型定义：https://gist.github.com/iambibhas/4705378
