我想将图例添加到我的ggplot中，并在图例中提供两个独立的标题，一个用于绿线，另一个用于红线。

library(ggplot2)
data <- data.frame(x = c(1, 2, 3, 4, 5), y = c(1, 4, 9, 16, 25))
plot <- ggplot(data, aes(x, y))

plot <- plot + geom_line(aes(color = "Green Line"), linetype = "solid")
plot <- plot + geom_line(aes(color = "Red Line"), linetype = "dashed")

plot <- plot + scale_color_manual(values = c("Green Line" = "green", "Red Line" = "red"),
                                  labels = c("Green Line Title", "Red Line Title"))

print(plot)