how to plot a line under subtitle

[perlatex]

In order to train myself, I try to reproduce this image, but don't know how to draw the red line under subtitle.

I tried to do it with ggtext, but failed

library(tidyverse)
library(ggtext)

d <- tibble::tribble(
  ~area, ~group, ~value,
  "Texas A&M", "white Students", 0.03,
  "Texas A&M", "Black Students", 0.07,
  "Umass Amherst", "white Students", 0.07,
  "Umass Amherst", "Black Students", 0.23,
  "UW-Milwaukee", "white Students", 0.13,
  "UW-Milwaukee", "Black Students", 0.31
)


d %>%
  mutate(
    across(group, as_factor),
  ) %>%
  ggplot(aes(x = group, y = value, color = group, fill = group)) +
  geom_col(width = 0.4) +
  geom_text(aes(label = scales::label_percent(scale = 100, accuracy = 1)(value)),
    vjust = -1,
    size = rel(6),
    fontface = "bold"
  ) +
  facet_wrap(vars(area), ncol = 3, scales = "free_y") +
  scale_x_discrete(
    labels = function(x) str_replace(x, " ", "\n"),
    expand = expansion(mult = .8)
  ) +
  scale_y_continuous(
    limits = c(0, 0.46),
    breaks = c(0, 0.2, 0.4),
    labels = scales::label_percent(scale = 100, accuracy = 1),
    expand = expansion(mult = 0)
  ) +
  scale_fill_manual(
    values = c("white Students" = "#252A4A", "Black Students" = "#F42F5D"),
    aesthetics = c("colour", "fill")
  ) +
  theme(
    legend.position = "none",
    plot.title = element_text(size = rel(2)),
    plot.subtitle = element_markdown(),
    plot.caption = element_text(size = 12, color = "grey50", hjust = 0),
    axis.text.y = element_text(size = rel(1.5)),
    axis.text.x = element_text(
      size = rel(1.5),
      face = "bold",
      color = c("#252A4A", "#F42F5D")
    ),
    axis.ticks = element_blank(),
    panel.background = element_rect(color = "white", fill = NA),
    panel.grid.major.y = element_line(
      colour = "gray",
      size = 0.8,
      linetype = "dotted"
    ),
    strip.background = element_blank(),
    strip.text = element_text(face = "bold", size = rel(1)),
    panel.spacing = unit(2, "lines")
  ) +
  labs(
    title = "Black students are regularly labeled a higher risk for failure\nthan White students",
    subtitle = "<span style = 'font-size:13pt; '>Percentage of student body labeled as high risk to not graduate within their <br> selected major</span><br>
                <span style = 'color:#F42F5D; '>---</span>",
    caption = "Sources: Texas A&M, University of Massachusetts Amherst, and University of Wisconsin–\nMilwaukee",
    x = NULL, y = NULL
  )

[perlatex]

a stupid way

library(tidyverse)
library(ggtext)

txt <- glue::glue("<span style='color:red'>", str_dup("-", 100), "</span>")

mtcars %>% 
  ggplot(aes(x = mpg, y = cyl)) +
  geom_point() +
  labs(
    title = "I <span style='color:red'> love </span> ggtext.",
    subtitle = txt
  ) +
  theme(
    plot.title = element_markdown(),
    plot.subtitle = element_markdown()
  )