code: public static WindowOver<Double> regrSlope(Expression<? extends Number> arg1, Expression<? extends Number> arg2) {
          return new WindowOver<Double>(Double.class, SQLOps.REGR_SLOPE, arg1, arg2);
      }
docs: REGR_SLOPE returns the slope of the line
  
  @param arg1 first arg
  @param arg2 second arg
  @return regr_slope(arg1, arg2)