Change dialog subtitle text

Submitted by sco..@..il.com

Assigned to Xfce Bug Triage

Link to original bug (#15543)

Description

Right click panel and select add item in panel sub menu.

Dialog says: "Add New Items" "Add new plugins to the panel"

Maybe this would be more correct: "Add new plugins, separators, and launchers to the panel"

Version: 4.13.5