$ sudo apt-get update
$ sudo apt-get install gedit-valatoys-plugin 

gedit-valatoys-plugin is installed in your system.

Make ensure the gedit-valatoys-plugin package were installed using the commands given below,

$ sudo dpkg-query -l | grep gedit-valatoys-plugin *

You will get with gedit-valatoys-plugin package name, version, architecture and description in a table

gedit-valatoys-plugin package basic information: