Append the task name to its note and let the user write a new one.
Clone the repo and link it in the Automation Configuration dialog in OmniFocus, or add it as a git submodule to the default plugin folder of OmniFocus. I recommend the latter for an easier synchronization with other devices.
cd ~/Library/Mobile Documents/iCloud~com~omnigroup~OmniFocus/Documents/Plug-Ins
git init
git submodule add https://github.com/xbot/omnifocus-plugin-refine-task.git refine-task
# For updating:
git submodule update --remote --recursive