You can make this even easier by installing
Press Ctrl-Shift-P to bring up Package Control
type install hit Enter to bring up Package Control: Install Package
type PackageResourceViewer hit Enter
To modify the Javascript function-(fun) snippet:
Bring up Package Control again (Ctrl+Shift+P)
type ope hit Enter to bring up PackageResourceViewer: Open Resource
type js hit Enter to browse the Javascript package
type fun& select function-(fun) and edit to your heart’s content ?
安装package ：
Package Resource Viewer
ctrl+ship+p调出package control，输入ope，选择PackageResourceViewer: Open Resource，然后输入你想要改变的语言类下面的快捷键，例如php,选择出来的选项，就能进去自由编辑了！太棒了！
快捷键内容如下：
改完之后会在目录下面创建一个备份的Snippets
C:\Users\user\AppData\Roaming\Sublime Text 3\Packages\PHP\Snippets
参考链接