Update documentation on interactive grid
Update documentation on interactive grid

This change will help users facing issue similar to https://github.com/Hammerspoon/hammerspoon/issues/1619

It explains the relationship between interactive grid and hints variable.
CommandPost/CommandPost-App,CommandPost/CommandPost-App,Hammerspoon/hammerspoon,cmsj/hammerspoon,Hammerspoon/hammerspoon,Hammerspoon/hammerspoon,cmsj/hammerspoon,latenitefilms/hammerspoon,asmagill/hammerspoon,asmagill/hammerspoon,CommandPost/CommandPost-App,asmagill/hammerspoon,asmagill/hammerspoon,latenitefilms/hammerspoon,Habbie/hammerspoon,CommandPost/CommandPost-App,latenitefilms/hammerspoon,CommandPost/CommandPost-App,Hammerspoon/hammerspoon,Habbie/hammerspoon,latenitefilms/hammerspoon,asmagill/hammerspoon,asmagill/hammerspoon,Habbie/hammerspoon,Habbie/hammerspoon,Hammerspoon/hammerspoon,latenitefilms/hammerspoon,Hammerspoon/hammerspoon,cmsj/hammerspoon,Habbie/hammerspoon,latenitefilms/hammerspoon,Habbie/hammerspoon,CommandPost/CommandPost-App,cmsj/hammerspoon,cmsj/hammerspoon,cmsj/hammerspoon