Add spellchecker scripts for Octave and run spellcheck of documentation interpreter/doccheck: New directory for spelling/grammar scripts. interpreter/doccheck/README: Instructions for using scripts. interpreter/doccheck/spellcheck: Script to spellcheck a Texinfo file. interpreter/doccheck/aspell.conf: GNU Aspell configuration file for Octave documentation. interpreter/doccheck/aspell-octave.en.pws: Private Aspell dictionary. interpreter/doccheck/add_to_aspell_dict: Script to add new Octave-specific words to private Aspell dictionary. interpreter/octave.texi: New @nospell macro which forces Aspell to ignore the word marked by the macro. interpreter/mk_doc_cache.m: Skip new @nospell macro when building doc_cache.

--- a/scripts/special-matrix/hankel.m
+++ b/scripts/special-matrix/hankel.m
@@ -18,7 +18,8 @@
 ## <http://www.gnu.org/licenses/>.
 
 ## -*- texinfo -*-
-## @deftypefn {Function File} {} hankel (@var{c}, @var{r})
+## @deftypefn  {Function File} {} hankel (@var{c})
+## @deftypefnx {Function File} {} hankel (@var{c}, @var{r})
 ## Return the Hankel matrix constructed given the first column @var{c}, and
 ## (optionally) the last row @var{r}.  If the last element of @var{c} is
 ## not the same as the first element of @var{r}, the last element of