安装说明： https://github.com/zsh-users/zsh-syntax-highlighting/blob/master/INSTALL.md
根据安装说明：
1.Clone this repository in oh-my-zsh’s plugins directory：
git clone https://github.com/zsh-users/zsh-syntax-highlighting.git ${ZSH_CUSTOM:-~/.oh-my-zsh/custom}/plugins/zsh-syntax-highlighting
2.Activate the plugin in ~/.zshrc：
plugins=( [plugins...] zsh-syntax-highlighting)
3.Restart zsh (such as by opening a new instance of your terminal emulator).
并没有要求在 ~/.zshrc 中写入以下这句命令语句：
source /root/.oh-my-zsh/custom/plugins/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh
