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.

--- a/scripts/special-matrix/toeplitz.m
+++ b/scripts/special-matrix/toeplitz.m
@@ -21,10 +21,11 @@
 ## @deftypefn  {Function File} {} toeplitz (@var{c})
 ## @deftypefnx {Function File} {} toeplitz (@var{c}, @var{r})
 ## Return the Toeplitz matrix constructed from the first column @var{c},
-## and (optionally) the first row @var{r}.  If the first element of @var{r}
-## is not the same as the first element of @var{c}, the first element of
-## @var{c} is used.  If the second argument is omitted, the first row is
-## taken to be the same as the first column.
+## and (optionally) the first row @var{r}.
+##
+## If the first element of @var{r} is not the same as the first element of
+## @var{c}, the first element of @var{c} is used.  If the second argument is
+## omitted, the first row is taken to be the same as the first column.
 ##
 ## A square Toeplitz matrix has the form:
 ## @tex