Fix in Tjur R² value calculation
Fix in Tjur R² value calculation

in case of reverse coding, Tjur R² gave a 0 result, but it should display the absolute value.

FransMeerhoff/jasp-desktop,AlexanderLyNL/jasp-desktop,jasp-stats/jasp-desktop,boutinb/jasp-desktop,vankesteren/jasp-desktop,vankesteren/jasp-desktop,boutinb/jasp-desktop,jasp-stats/jasp-desktop,vankesteren/jasp-desktop,AlexanderLyNL/jasp-desktop,FransMeerhoff/jasp-desktop,TimKDJ/jasp-desktop,AlexanderLyNL/jasp-desktop,jasp-stats/jasp-desktop,TimKDJ/jasp-desktop,FransMeerhoff/jasp-desktop,AlexanderLyNL/jasp-desktop,AlexanderLyNL/jasp-desktop,TimKDJ/jasp-desktop,FransMeerhoff/jasp-desktop,FransMeerhoff/jasp-desktop,boutinb/jasp-desktop,boutinb/jasp-desktop,boutinb/jasp-desktop,AlexanderLyNL/jasp-desktop,FransMeerhoff/jasp-desktop,TimKDJ/jasp-desktop,jasp-stats/jasp-desktop,vankesteren/jasp-desktop,TimKDJ/jasp-desktop,boutinb/jasp-desktop,jasp-stats/jasp-desktop,vankesteren/jasp-desktop,jasp-stats/jasp-desktop,boutinb/jasp-desktop,vankesteren/jasp-desktop,boutinb/jasp-desktop,AlexanderLyNL/jasp-desktop,TimKDJ/jasp-desktop,AlexanderLyNL/jasp-desktop,FransMeerhoff/jasp-desktop,TimKDJ/jasp-desktop,FransMeerhoff/jasp-desktop,TimKDJ/jasp-desktop,vankesteren/jasp-desktop,jasp-stats/jasp-desktop,jasp-stats/jasp-desktop,vankesteren/jasp-desktop