@Mkawette
If you deleted it from the 'mods' folder, find the equivalent 'content.xml' from the 'game' folder & copy it to where you deleted the 'mods' folder one.

If you deleted it from the 'game' folder (ie original vanilla install of GTAV) then Google how to verify the game files for your version of the game & do that & it will re-download the '.rpf' that the 'content.xml' was in & give you a fresh copy