Remove border between the header and body

Question Want to remove the border between the header and body, but border_bottom = "" does not work.

Context I have a screenshot uploaded. I need to highlighted border to be removed. Is it possible?

A simple example of what I did

library(r2rtf)
tbl <- r2rtf_adae %>%
  count(TRTA, AEDECOD) %>%
  pivot_wider(names_from = TRTA, values_from = n, values_fill = 0)
#> Error in r2rtf_adae %>% count(TRTA, AEDECOD) %>% pivot_wider(names_from = TRTA, : could not find function "%>%"

head(tbl) %>%
  rtf_colheader(
    colheader = "Adverse Events | Placebo | Xanomeline High Dose | Xanomeline Low Dose",
    col_rel_width = c(3, 2, 2, 2),
    border_bottom = ""
  ) %>%
  rtf_body(col_rel_width = c(3, 2, 2, 2)) %>%
  rtf_encode() %>%
  write_rtf("output/intro-ae3.rtf")
#> Error in head(tbl) %>% rtf_colheader(colheader = "Adverse Events | Placebo | Xanomeline High Dose | Xanomeline Low Dose", : could not find function "%>%"

^{Created on 2023-10-16 with reprex v2.0.2}

Screenshots

Merck / r2rtf

Remove border between the header and body #203