Clarify NULL default wording in args-density-controls template

Author: utkarshpawade

man-roxygen/args-density-controls.R

@@ -1,5 +1,5 @@
 #' @param bw,adjust,kernel,n_dens,bounds Optional arguments passed to
 #'   [stats::density()] (and `bounds` to [ggplot2::stat_density()]) to override
 #'   default kernel density estimation parameters or truncate the density
-#'   support. `bw` defaults to `"nrd0"`, `adjust` to `1`, `kernel` to
-#'   `"gaussian"`, and `n_dens` to `1024`.
+#'   support. If `NULL` (default), `bw` is set to `"nrd0"`, `adjust` to `1`,
+#'   `kernel` to `"gaussian"`, and `n_dens` to `1024`.