Add the annotation function (bug #43282) * NEWS: add annotation * plot.txi: add annotation in same chapter as x/y/zlabel, title... * __unimplemented__: remove annotation from the list * scripts/plot/draw/annotation.m: new function file * axes.m: restack figure children so that the annotation axes is always drawn on top * axes.m: replace "parent" variable by "cf" for concistency * clf.m: make "clf" delete the hidden annotation axes for matlab compatibility * clf.m: avoid flashing a figure in the last test.