doc: Update documentation for functions returning a graphics handle h (Bug #34761) * voronoi.m, image.m, imagesc.m, imshow.m, area.m, bar.m, barh.m, clabel.m, clf.m, compass.m, ezcontour.m, ezcontourf.m, ezmesh.m, ezmeshc.m, ezplot.m, ezplot3.m, ezpolar.m, ezsurf.m, ezsurfc.m, feather.m, fill.m, findall.m, findobj.m, loglog.m, mesh.m, pareto.m, patch.m, pie.m, pie3.m, plot.m, polar.m, quiver.m, quiver3.m, rectangle.m, ribbon.m, rose.m, scatter.m, scatter3.m, semilogx.m, semilogy.m, slice.m, stem.m, surf.m, surface.m, text.m, title.m, trimesh.m, triplot.m, trisurf.m, xlabel.m, ylabel.m, zlabel.m: Update documentation for functions returning a graphics handle h.

--- a/scripts/plot/loglog.m	Mon Dec 05 17:13:35 2011 -0800
+++ b/scripts/plot/loglog.m	Tue Dec 06 13:09:17 2011 -0800
@@ -26,6 +26,8 @@
 ## Produce a two-dimensional plot using log scales for both axes.  See
 ## the documentation of @code{plot} for a description of the arguments
 ## that @code{loglog} will accept.
+##
+## The optional return value @var{h} is a graphics handle to the created plot.
 ## @seealso{plot, semilogx, semilogy}
 ## @end deftypefn