doc: Update more docstrings to have one sentence summary as first line. Reviewed specfun, special-matrix, testfun, and time script directories. * scripts/specfun/expint.m, scripts/specfun/isprime.m, scripts/specfun/legendre.m, scripts/specfun/primes.m, scripts/specfun/reallog.m, scripts/specfun/realsqrt.m, scripts/special-matrix/gallery.m, scripts/special-matrix/hadamard.m, scripts/special-matrix/hankel.m, scripts/special-matrix/hilb.m, scripts/special-matrix/invhilb.m, scripts/special-matrix/magic.m, scripts/special-matrix/pascal.m, scripts/special-matrix/rosser.m, scripts/special-matrix/toeplitz.m, scripts/special-matrix/vander.m, scripts/special-matrix/wilkinson.m, scripts/testfun/assert.m, scripts/testfun/demo.m, scripts/testfun/example.m, scripts/testfun/fail.m, scripts/testfun/rundemos.m, scripts/testfun/runtests.m, scripts/testfun/speed.m, scripts/time/asctime.m, scripts/time/calendar.m, scripts/time/clock.m, scripts/time/ctime.m, scripts/time/datenum.m, scripts/time/datestr.m, scripts/time/datevec.m, scripts/time/etime.m, scripts/time/is_leap_year.m, scripts/time/now.m, scripts/time/weekday.m: Update more docstrings to have one sentence summary as first line.

% this script is intended to be Matlab compatible
% first, run the script
%
%   ./build_bc_overloads_tests.sh overloads_only
%
% to generate the overloaded functions.
%
ex.double = 1;
ex.single = single (1);
ex.logical = true;
ex.char = 'char';
ex.int8  = int8 (1);
ex.int16 = int16 (1);
ex.int32 = int32 (1);
ex.int64 = int64 (1);
ex.uint8  = uint8 (1);
ex.uint16 = uint16 (1);
ex.uint32 = uint32 (1);
ex.uint64 = uint64 (1);
ex.cell = {};
ex.struct = struct ();
ex.function_handle = @numel;

f = fieldnames (ex);
n = numel (f);

fid = fopen ('bc_overloads_expected','w');
fid
for i = 1:n
  for j = 1:n
    s = tbcover (ex.(f{i}), ex.(f{j}));
    fprintf (fid, '%s %s %s\n', f{i}, f{j}, s);
  end
end
fclose (fid)