remove add_header_left entirely
update rd files
improve package documentation based on @wibeasley's suggestion
diff --git a/man/add_header_above.Rd b/man/add_header_above.Rd
index cbe6988..d879bc7 100644
--- a/man/add_header_above.Rd
+++ b/man/add_header_above.Rd
@@ -7,13 +7,13 @@
 add_header_above(kable_input, header = NULL, bold = F, italic = F)
 }
 \arguments{
-\item{kable_input}{Output of `knitr::kable()` with `format` specified}
+\item{kable_input}{Output of \code{knitr::kable()} with \code{format} specified}
 
-\item{header}{A (named) character vector with `colspan` as values. For
-example, `c(" " = 1, "title" = 2)` can be used to create a new header row
+\item{header}{A (named) character vector with \code{colspan} as values. For
+example, \code{c(" " = 1, "title" = 2)} can be used to create a new header row
 for a 3-column table with "title" spanning across column 2 and 3. For
-convenience, when `colspan` equals to 1, users can drop the ` = 1` part.
-As a result, `c(" ", "title" = 2)` is the same as `c(" " = 1, "title" = 2)`.}
+convenience, when \code{colspan} equals to 1, users can drop the \code{= 1} part.
+As a result, \code{c(" ", "title" = 2)} is the same as \code{c(" " = 1, "title" = 2)}.}
 
 \item{bold}{A T/F value to control whether the text should be bolded.}
 
@@ -21,9 +21,9 @@
 }
 \description{
 Tables with multiple rows of header rows are extremely useful
-to demonstrate grouped data. This function takes the output of a `kable()`
+to demonstrate grouped data. This function takes the output of a \code{kable()}
 function and adds an header row on top of it. This function can work with
-both `HTML` and `LaTeX` outputs
+both \code{HTML} and \code{LaTeX} outputs
 }
 \examples{
 x <- knitr::kable(head(mtcars), "html")