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/mesh.m
+++ b/scripts/plot/mesh.m
@@ -32,6 +32,9 @@
 ## The color of the mesh is derived from the @code{colormap}
 ## and the value of @var{z}.  Optionally the color of the mesh can be
 ## specified independent of @var{z}, by adding a fourth matrix, @var{c}.
+##
+## The optional return value @var{h} is a graphics handle to the created
+## suface object.
 ## @seealso{colormap, contour, meshgrid, surf}
 ## @end deftypefn
 
@@ -58,3 +61,7 @@
   endif
 
 endfunction
+
+
+%% FIXME: Need demo or test for function
+