allow fig_caption to be modified in html_letter

this fixes #234

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: pagedown
 Type: Package
 Title: Paginate the HTML Output of R Markdown with CSS for Print
-Version: 0.15.1
+Version: 0.15.2
 Authors@R: c(
   person("Yihui", "Xie", role = c("aut", "cre"), email = "xie@yihui.name", comment = c(ORCID = "0000-0003-0645-5666")),
   person("Romain", "Lesur", role = c("aut", "cph"), comment = c(ORCID = "0000-0002-0721-5595")),

NEWS.md

@@ -1,5 +1,8 @@
 # CHANGES IN pagedown VERSION 0.16
 
+## MINOR CHANGES
+
+- Document that the `html_letter()` output format modifies the default value of the `fig_caption` parameter and allow the user to change it (thanks, @NewGraphEnvironment, #234).
 
 # CHANGES IN pagedown VERSION 0.15
 

R/paged.R

@@ -51,14 +51,15 @@ html_paged = function(
 
 #' Create a letter in HTML
 #'
-#' This output format is similar to \code{html_paged}. The only difference is in
-#' the default stylesheets. See \url{https://pagedown.rbind.io/html-letter/} for
-#' an example.
-#' @param ...,css Arguments passed to \code{\link{html_paged}()}.
+#' This output format is similar to \code{html_paged}. The only differences are
+#' in the default stylesheets and the default value of the \code{fig_caption}
+#' parameter which is set to \code{FALSE}. See
+#' \url{https://pagedown.rbind.io/html-letter/} for an example.
+#' @param ...,css,fig_caption Arguments passed to \code{\link{html_paged}()}.
 #' @return An R Markdown output format.
 #' @export
-html_letter = function(..., css = c('default', 'letter')) {
-  html_paged(..., css = css, fig_caption = FALSE)
+html_letter = function(..., css = c('default', 'letter'), fig_caption = FALSE) {
+  html_paged(..., css = css, fig_caption = fig_caption)
 }
 
 #' Create a book for Chapman & Hall/CRC