improve see also links in docs of color scales

add scale_(color|fill)_discrete to @family color scales

remove explit @Seealso links from ?scale_(color|fill)_(continous|binned)
that are redundant due to links provided through @family

add @Seealso links for discrete_scale continous_scale and binned_scales
to scale_(fill|color)_(discrete|binned|continous) as appropiate

Author: Jan Gleixner

R/scale-colour.R

@@ -31,9 +31,7 @@
 #'   * "gradient" (the default)
 #'   * "viridis"
 #'   * A function that returns a continuous colour scale.
-#' @seealso  [continuous_scale()], [scale_colour_gradient()], [scale_colour_viridis_c()],
-#'   [scale_colour_steps()], [scale_colour_viridis_b()], [scale_fill_gradient()],
-#'   [scale_fill_viridis_c()], [scale_fill_steps()], and [scale_fill_viridis_b()]
+#' @seealso  [continuous_scale()] and [binned_scale()]
 #'
 #'   The documentation on [colour aesthetics][aes_colour_fill_alpha].
 #' @family colour scales
@@ -190,6 +188,8 @@ scale_fill_binned <- function(..., palette = NULL, aesthetics = "fill", guide =
 #'   * A function that returns a discrete colour/fill scale (e.g., [scale_fill_hue()],
 #'   [scale_fill_brewer()], etc).
 #' @export
+#' @seealso [discrete_scale()]
+#' @family colour scales
 #' @seealso
 #' The `r link_book("discrete colour scales section", "scales-colour#sec-colour-discrete")`
 #' @examples