Better help for color palettes

src/slang/color/palettes.sl

@@ -206,6 +206,12 @@ add_color_palette("sron:landcover", [0x5566aa, 0x117733, 0x44aa66, 0x55aa22, 0x6
 %  The SRON colors are defined in Paul Tol's technical note (\code{https://personal.sron.nl/~pault/data/colourschemes.pdf})
 %  and provides a set of colors for qualitative, diverging, and sequential
 %  representations.
+%
+%  Note: To get the original set of colors (was provided by \code{get_sron_colors})
+%  use \code{get_color_palette("sron-rainbow", n);} for diverging and sequential
+%  there are no direct matches. See the other color palette options.
+%
+%\seealso{get_color_palette_names, palette--sron-rainbow}
 %!%-
 %}}}
 
@@ -312,7 +318,7 @@ private define blend_palette (n)
 %
 %  The qualifier \code{space} allows to control in what space the interpolation
 %  is done. This either must be one of the known color spaces "hsl", "hsluv", 
-%  "hpluv", or "rgb", or a tuble (list with 2 elements) with references
+%  "hpluv", or "rgb", or a tuple (list with 2 elements) with references
 %  to two functions. The first must take three arguments (R,G,B) as 8 bit
 %  encoded colors and convert it to the color space variables (x,y,z). The
 %  second converts back (x,y,z) -> (R,G,B).
@@ -539,6 +545,13 @@ private define colormap_palette (n, name)
 %  It returns \code{len} values from a linear mapping of the
 %  given colormap. The colors are constructed from palette--blend
 %  and forwards all qualifiers to this constructor.
+%
+%  Note: This function is used only if the given \code{name} is
+%  a colormap (and does not match a palette name, see \code{png_get_colormap_names}),
+%  to construct a %  set of colors from a color array see
+%  palette--blend.
+%
+%\seealso{png_get_colormap_names, palette--name}
 %!%-
 {
 #ifexists png_add_colormap