doc: Update more docstrings to have one sentence summary as first line. Reviewed miscellaneous, sparse, strings in scripts directory. * scripts/miscellaneous/bzip2.m, scripts/miscellaneous/citation.m, scripts/miscellaneous/compare_versions.m, scripts/miscellaneous/computer.m, scripts/miscellaneous/debug.m, scripts/miscellaneous/dir.m, scripts/miscellaneous/edit.m, scripts/miscellaneous/error_ids.m, scripts/miscellaneous/fileattrib.m, scripts/miscellaneous/fullfile.m, scripts/miscellaneous/genvarname.m, scripts/miscellaneous/gzip.m, scripts/miscellaneous/mkoctfile.m, scripts/miscellaneous/news.m, scripts/miscellaneous/open.m, scripts/miscellaneous/parseparams.m, scripts/miscellaneous/recycle.m, scripts/miscellaneous/run.m, scripts/miscellaneous/swapbytes.m, scripts/miscellaneous/tar.m, scripts/miscellaneous/tmpnam.m, scripts/miscellaneous/unpack.m, scripts/miscellaneous/what.m, scripts/sparse/bicg.m, scripts/sparse/bicgstab.m, scripts/sparse/cgs.m, scripts/sparse/colperm.m, scripts/sparse/eigs.m, scripts/sparse/etreeplot.m, scripts/sparse/gmres.m, scripts/sparse/gplot.m, scripts/sparse/ichol.m, scripts/sparse/ilu.m, scripts/sparse/pcg.m, scripts/sparse/pcr.m, scripts/sparse/qmr.m, scripts/sparse/spaugment.m, scripts/sparse/spconvert.m, scripts/sparse/spdiags.m, scripts/sparse/spfun.m, scripts/sparse/spones.m, scripts/sparse/sprandsym.m, scripts/sparse/spstats.m, scripts/sparse/spy.m, scripts/sparse/svds.m, scripts/sparse/treelayout.m, scripts/sparse/treeplot.m, scripts/strings/base2dec.m, scripts/strings/bin2dec.m, scripts/strings/blanks.m, scripts/strings/cstrcat.m, scripts/strings/deblank.m, scripts/strings/dec2base.m, scripts/strings/dec2bin.m, scripts/strings/dec2hex.m, scripts/strings/findstr.m, scripts/strings/hex2dec.m, scripts/strings/index.m, scripts/strings/isletter.m, scripts/strings/isstrprop.m, scripts/strings/mat2str.m, scripts/strings/ostrsplit.m, scripts/strings/regexptranslate.m, scripts/strings/rindex.m, scripts/strings/str2num.m, scripts/strings/strcat.m, scripts/strings/strchr.m, scripts/strings/strjoin.m, scripts/strings/strjust.m, scripts/strings/strmatch.m, scripts/strings/strsplit.m, scripts/strings/strtok.m, scripts/strings/strtrim.m, scripts/strings/strtrunc.m, scripts/strings/substr.m, scripts/strings/untabify.m, scripts/time/datenum.m: Update more docstrings to have one sentence summary as first line.

## Copyright (C) 2015 Rik Wehbring
##
## This file is part of Octave.
##
## Octave is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 3 of the License, or (at
## your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, see
## <http://www.gnu.org/licenses/>.

## Test ordering of complex values by magnitude and then by phase
%!test
%! x = [0 i 1+i 2 3i 3+4i];
%! assert (sort (x, "descend"), fliplr (x));
%! assert (sort (single (x), "descend"), fliplr (single (x)));

%!test
%! x = [1, -1, i, -i];
%! xs = [-i, 1, i, -1];
%! assert (sort (x), xs);
%! assert (sort (x, "descend"), fliplr (xs));
%! assert (sort (single (x)), single (xs));
%! assert (sort (single (x), "descend"), fliplr (single (xs)));

## bug #44071, issorted incorrect because it uses different sort routine.
%!assert (issorted ([1, -1, i, -i]), false)
%!assert (issorted (single ([1, -1, i, -i])), false)

## bug #43313, -1 is both '>' and '==' to (-1 - 0i)
%!test
%! assert (complex(-1,0) == complex(-1,-0), true);
%! assert (complex(-1,0) > complex(-1,-0), false);
%! assert (complex(-1,0) < complex(-1,-0), false);

## Test that sort and issorted both agree on boundary case
%!test
%! x = [complex(-1,0), complex(-1,-0), i, -i, 1];
%! xs = sort (x);
%! xf = single (x);
%! xfs = sort (xf);
%! assert (issorted (xs));
%! assert (issorted (xfs));
%! assert (double (xfs), xs);

## Finally, test that sort and issorted agree on NaNs
%!test
%! x = [complex(NaN,-1), complex(NaN,NaN), ...
%!      complex(-1,0), complex(-1,-0), i, -i, 1, ...
%!      complex(1,NaN)];
%! xs = sort (x);
%! xf = single (x);
%! xfs = sort (xf);
%! assert (issorted (xs));
%! assert (issorted (xfs));
%! assert (double (xfs), xs);