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/guidata.m
+++ b/scripts/plot/guidata.m
@@ -17,8 +17,17 @@
 ## <http://www.gnu.org/licenses/>.
 
 ## -*- texinfo -*-
-## @deftypefn  {Function File} {@var{data} =} guidata (@var{handle})
-## @deftypefnx {Function File} {} guidata (@var{handle}, @var{data})
+## @deftypefn  {Function File} {@var{data} =} guidata (@var{h})
+## @deftypefnx {Function File} {} guidata (@var{h}, @var{data})
+## Query or set user-custom GUI data.
+##
+## The GUI data is stored in the figure handle @var{h}.  If @var{h} is not a
+## figure handle then it's parent figure will be used for storage.
+##
+## @var{data} must be a single object which means it is usually preferable
+## for it to be a data container such as a cell array or struct.
+##
+## @seealso{getappdata, setappdata, get, set, getpref, setpref}
 ## @end deftypefn
 
 ## Author: goffioul