improved save_kable and added webshot support
diff --git a/man/save_kable.Rd b/man/save_kable.Rd
index e5bad7b..0b80071 100644
--- a/man/save_kable.Rd
+++ b/man/save_kable.Rd
@@ -4,17 +4,21 @@
 \alias{save_kable}
 \title{Save kable to files}
 \usage{
-save_kable(x, file, bs_theme = "simplex", self_contained = TRUE)
+save_kable(x, file, bs_theme = "simplex", self_contained = TRUE, ...)
 }
 \arguments{
 \item{x}{A piece of HTML code for tables, usually generated by kable and
 kableExtra}
 
-\item{file}{save to files}
+\item{file}{save to files. If the input table is in HTML and the output file
+ends with \code{.png}, \code{.pdf} and \code{.jpeg}, \code{webshot} will be used to do the
+conversion}
 
 \item{bs_theme}{Which Bootstrap theme to use}
 
 \item{self_contained}{Will the files be self-contained?}
+
+\item{...}{Additional variables being passed to \code{webshot::webshot}.`}
 }
 \description{
 Save kable to files