Crosslink aes and aes_eval docs

Author: teunbrand

R/aes-evaluation.r

@@ -1,9 +1,10 @@
 #' Control aesthetic evaluation
 #'
-#' Most aesthetics are mapped from variables found in the data. Sometimes,
-#' however, you want to delay the mapping until later in the rendering process.
-#' ggplot2 has three stages of the data that you can map aesthetics from, and
-#' three functions to control at which stage aesthetics should be evaluated.
+#' Most [aesthetics][aes()] are mapped from variables found in the data.
+#' Sometimes, however, you want to delay the mapping until later in the
+#' rendering process. ggplot2 has three stages of the data that you can map
+#' aesthetics from, and three functions to control at which stage aesthetics
+#' should be evaluated.
 #'
 #' @usage # These functions can be used inside the `aes()` function
 #' # used as the `mapping` argument in layers, for example:

R/aes.r

@@ -31,6 +31,8 @@ NULL
 #'   are typically omitted because they are so common; all other aesthetics must be named.
 #' @seealso [vars()] for another quoting function designed for
 #'   faceting specifications.
+#'
+#'   [Delayed evaluation][aes_eval] for working with computed variables.
 #' @return A list with class `uneval`. Components of the list are either
 #'   quosures or constants.
 #' @export