doc: Add missing doc for `add_layer_to_tree`

man/add_layer_to_tree.Rd

+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/addLayer.R
+\name{add_layer_to_tree}
+\alias{add_layer_to_tree}
+\title{Internal function}
+\usage{
+add_layer_to_tree(tree)
+}
+\arguments{
+\item{tree}{A tree data frame from \code{\link[=getTreeranger]{getTreeranger()}}.}
+}
+\value{
+A tree data frame with \code{layer} added.
+}
+\description{
+This function adds the respective layer to the different nodes in a tree.
+The tree has to be prepared by getTree function.
+}
+\seealso{
+\code{\link[=addLayer]{addLayer()}}
+}
+\keyword{internal}