attemp to fix line breaking issue of doc

R-package/R/xgb.train.R

@@ -24,10 +24,11 @@
 #'    watchlist=list(validation1=mat1, validation2=mat2) to watch
 #'    the performance of each round's model on mat1 and mat2
 #'
-#' @param obj customized objective function. Given prediction and dtrain, 
-#'   return gradient and second order gradient.
-#' @param feval custimized evaluation function. Given prediction and dtrain,
-#'   return a \code{list(metric='metric-name', value='metric-value')}.
+#' @param obj customized objective function. Returns gradient and second order 
+#'   gradient with given prediction and dtrain, 
+#' @param feval custimized evaluation function. Returns 
+#'   \code{list(metric='metric-name', value='metric-value')} with given 
+#'   prediction and dtrain,
 #' @param ... other parameters to pass to \code{params}.
 #' 
 #' @details