doc: Rewrite docstrings for most plot functions. Emphasize clarity, use common "voice", and increase density of seealso links. * doc/interpreter/plot.txi: Add @findex entries that were in xlim.m * scripts/miscellaneous/getappdata.m scripts/miscellaneous/setappdata.m, scripts/plot/allchild.m, scripts/plot/ancestor.m, scripts/plot/area.m, scripts/plot/axes.m, scripts/plot/axis.m, scripts/plot/bar.m, scripts/plot/barh.m, scripts/plot/box.m, scripts/plot/caxis.m, scripts/plot/cla.m, scripts/plot/clabel.m, scripts/plot/clf.m, scripts/plot/close.m, scripts/plot/closereq.m, scripts/plot/colorbar.m, scripts/plot/comet.m, scripts/plot/comet3.m, scripts/plot/compass.m, scripts/plot/contour.m, scripts/plot/contour3.m, scripts/plot/contourc.m, scripts/plot/contourf.m, scripts/plot/copyobj.m, scripts/plot/cylinder.m, scripts/plot/daspect.m, scripts/plot/diffuse.m, scripts/plot/ellipsoid.m, scripts/plot/errorbar.m, scripts/plot/ezcontour.m, scripts/plot/ezcontourf.m, scripts/plot/ezmesh.m, scripts/plot/ezmeshc.m, scripts/plot/ezplot.m, scripts/plot/ezplot3.m, scripts/plot/ezpolar.m, scripts/plot/ezsurf.m, scripts/plot/ezsurfc.m, scripts/plot/feather.m, scripts/plot/figure.m, scripts/plot/fill.m, scripts/plot/findall.m, scripts/plot/findobj.m, scripts/plot/fplot.m, scripts/plot/gca.m, scripts/plot/gcbf.m, scripts/plot/gcbo.m, scripts/plot/gcf.m, scripts/plot/gco.m, scripts/plot/ginput.m, scripts/plot/graphics_toolkit.m, scripts/plot/grid.m, scripts/plot/gtext.m, scripts/plot/guidata.m, scripts/plot/guihandles.m, scripts/plot/hdl2struct.m, scripts/plot/hggroup.m, scripts/plot/hidden.m, scripts/plot/hist.m, scripts/plot/hold.m, scripts/plot/ishghandle.m, scripts/plot/ishold.m, scripts/plot/isocolors.m, scripts/plot/isprop.m, scripts/plot/legend.m, scripts/plot/line.m, scripts/plot/linkprop.m, scripts/plot/loglog.m, scripts/plot/loglogerr.m, scripts/plot/mesh.m, scripts/plot/meshc.m, scripts/plot/meshgrid.m, scripts/plot/meshz.m, scripts/plot/newplot.m, scripts/plot/orient.m, scripts/plot/pareto.m, scripts/plot/patch.m, scripts/plot/pcolor.m, scripts/plot/peaks.m, scripts/plot/pie.m, scripts/plot/pie3.m, scripts/plot/plot.m, scripts/plot/plot3.m, scripts/plot/plotmatrix.m, scripts/plot/plotyy.m, scripts/plot/polar.m, scripts/plot/print.m, scripts/plot/quiver.m, scripts/plot/quiver3.m, scripts/plot/rectangle.m, scripts/plot/refresh.m, scripts/plot/refreshdata.m, scripts/plot/ribbon.m, scripts/plot/rose.m, scripts/plot/saveas.m, scripts/plot/scatter.m, scripts/plot/scatter3.m, scripts/plot/semilogx.m, scripts/plot/semilogxerr.m, scripts/plot/semilogy.m, scripts/plot/semilogyerr.m, scripts/plot/shading.m, scripts/plot/shg.m, scripts/plot/shrinkfaces.m, scripts/plot/slice.m, scripts/plot/specular.m, scripts/plot/sphere.m, scripts/plot/stairs.m, scripts/plot/stem.m, scripts/plot/stem3.m, scripts/plot/struct2hdl.m, scripts/plot/subplot.m, scripts/plot/surf.m, scripts/plot/surface.m, scripts/plot/surfc.m, scripts/plot/surfl.m, scripts/plot/tetramesh.m, scripts/plot/text.m, scripts/plot/title.m, scripts/plot/trimesh.m, scripts/plot/triplot.m, scripts/plot/trisurf.m, scripts/plot/view.m, scripts/plot/waitbar.m, scripts/plot/waitforbuttonpress.m, scripts/plot/waterfall.m, scripts/plot/whitebg.m, scripts/plot/xlabel.m, scripts/plot/xlim.m, scripts/plot/ylabel.m, scripts/plot/ylim.m, scripts/plot/zlabel.m, scripts/plot/zlim.m: Rewrite docstrings for most plot functions. Emphasize clarity, use common "voice", and increase density of seealso links.

--- a/scripts/plot/legend.m
+++ b/scripts/plot/legend.m
@@ -28,13 +28,16 @@
 ## @deftypefnx {Function File} {} legend ("@var{option}")
 ## @deftypefnx {Function File} {[@var{hleg}, @var{hleg_obj}, @var{hplot}, @var{labels}] =} legend (@dots{})
 ##
-## Display a legend for the axes with handle @var{hax}, or the current axes,
-## using the specified strings as labels.  Legend entries may be specified
-## as individual character string arguments, a character array, or a cell
-## array of character strings.  If the handles, @var{hobjs}, are not specified
-## then the legend's strings will be associated with the axes' descendants.
-## @code{legend} works on line graphs, bar graphs, etc.
-## A plot must exist before legend is called.
+## Display a legend for the current axes using the specified strings as labels.
+##
+## Legend entries may be specified as individual character string arguments,
+## a character array, or a cell array of character strings.
+##
+## If the first argument @var{hax} is an axes handle, then plot into this axis,
+## rather than the current axes returned by @code{gca}.  If the handles,
+## @var{hobjs}, are not specified then the legend's strings will be associated
+## with the axes' descendants.  @code{legend} works on line graphs,
+## bar graphs, etc.  A plot must exist before legend is called.
 ##
 ## The optional parameter @var{pos} specifies the location of the legend
 ## as follows:
@@ -102,7 +105,7 @@
 ## @item "right"
 ##   Place label text to the right of the keys
 ##
-## @item  "off"
+## @item "off"
 ##   Delete the legend object
 ## @end table
 ##
@@ -126,6 +129,10 @@
 ## is taken from the DisplayName property of graphics objects.  If no
 ## labels or DisplayNames are available, then the label text is simply
 ## "data1", "data2", @dots{}, @nospell{"dataN"}.
+##
+## Implementation Note: A legend is implemented as an additional axes object
+## of the current figure with the "tag" set to "legend".  Properties of the
+## legend object may be manipulated directly by using @code{set}.
 ## @end deftypefn
 
 function [hlegend2, hobjects2, hplot2, text_strings2] = legend (varargin)