Edit it with Notepad++ (or any text editor readily available).
You can use the Game Boost feature of RegInOut System Utilities to speed up GTA V and fix its lagging problem. It is recommended you also turn unwanted services off. If none-of-the-above-mentioned steps worked your system isn’t fit enough to run GTA V at its default settings. (You can use this if you work primarily with non-graphics-intensive apps, such as Word and Outlook.) For GTA V, you have to disable it. This plan slows down your processor to maximize the battery life.