Adjust script docx->md

The report could not be knit if the text background color was not white in the docx file.

Author: RCinbo

source/R/habitatauteurs_from_docx.R

@@ -65,6 +65,7 @@ for (hoofdstuk in c("zilt", "kustduin", "water", "heide", "gras", "veen",
       str_replace_all("\\\\", "\\") %>% #otherwise, double backslash is printed in the md file
       str_replace_all("\\[", "[") %>%
       str_replace_all("\\]", "]") %>%
+      str_replace_all("\\{.mark\\}", "") %>%
       writeLines(useBytes = TRUE,
                  con = find_root_file("source/bookdown/habitatauteurs_paragrafen",
                                       sprintf("%s_%s.md",hoofdstuk,x),