Try the following:
#' @title
#' Square a number
#'
#' @description
#' Takes in any numeric value and squares it
#'
#' @param x A value to be squared
#' @return The square of the input
#'
#' @export
#' @examples
#' square(2) # 2 squared
square <- function(x)
{
return(x^2)
}
Also, make sure you play with the latest roxygen2
package.