remove add_header_left entirely
update rd files
improve package documentation based on @wibeasley's suggestion
diff --git a/man/row_spec.Rd b/man/row_spec.Rd
index deb7912..d8237ad 100644
--- a/man/row_spec.Rd
+++ b/man/row_spec.Rd
@@ -7,7 +7,7 @@
 row_spec(kable_input, row, bold = FALSE, italic = FALSE)
 }
 \arguments{
-\item{kable_input}{Output of `knitr::kable()` with `format` specified}
+\item{kable_input}{Output of \code{knitr::kable()} with \code{format} specified}
 
 \item{row}{A numeric value indicating which row to be selected. You don't
 need to count in header rows or group labeling rows.}