doc: Update more docstrings to have one sentence summary as first line. Reviewed io, java, linear-algebra, prefs, and set script directories. * scripts/io/beep.m, scripts/io/dlmwrite.m, scripts/io/importdata.m, scripts/io/strread.m, scripts/io/textread.m, scripts/java/javaArray.m, scripts/java/java_get.m, scripts/java/java_set.m, scripts/java/javaaddpath.m, scripts/java/javachk.m, scripts/java/javaclasspath.m, scripts/java/javamem.m, scripts/java/javarmpath.m, scripts/linear-algebra/bandwidth.m, scripts/linear-algebra/commutation_matrix.m, scripts/linear-algebra/cond.m, scripts/linear-algebra/condest.m, scripts/linear-algebra/cross.m, scripts/linear-algebra/duplication_matrix.m, scripts/linear-algebra/expm.m, scripts/linear-algebra/housh.m, scripts/linear-algebra/isdefinite.m, scripts/linear-algebra/ishermitian.m, scripts/linear-algebra/issymmetric.m, scripts/linear-algebra/istril.m, scripts/linear-algebra/istriu.m, scripts/linear-algebra/krylov.m, scripts/linear-algebra/logm.m, scripts/linear-algebra/normest.m, scripts/linear-algebra/null.m, scripts/linear-algebra/onenormest.m, scripts/linear-algebra/orth.m, scripts/linear-algebra/qzhess.m, scripts/linear-algebra/rank.m, scripts/linear-algebra/rref.m, scripts/linear-algebra/vech.m, scripts/path/matlabroot.m, scripts/prefs/addpref.m, scripts/prefs/getpref.m, scripts/prefs/ispref.m, scripts/prefs/rmpref.m, scripts/prefs/setpref.m, scripts/set/powerset.m, scripts/set/setdiff.m: Update more docstrings to have one sentence summary as first line.

--- a/scripts/linear-algebra/duplication_matrix.m
+++ b/scripts/linear-algebra/duplication_matrix.m
@@ -23,35 +23,35 @@
 ##  $D_n$
 ## @end tex
 ## @ifnottex
-##  @nospell{@math{Dn}}
+## @nospell{@math{Dn}}
 ## @end ifnottex
-##  which is the unique
+## which is the unique
 ## @tex
 ##  $n^2 \times n(n+1)/2$
 ## @end tex
 ## @ifnottex
-##  @math{n^2} by @math{n*(n+1)/2}
+## @math{n^2} by @math{n*(n+1)/2}
 ## @end ifnottex
-##  matrix such that
+## matrix such that
 ## @tex
 ##  $D_n * {\rm vech} (A) = {\rm vec} (A)$
 ## @end tex
 ## @ifnottex
-##  @nospell{@math{Dn vech (A) = vec (A)}}
+## @nospell{@math{Dn vech (A) = vec (A)}}
 ## @end ifnottex
-##  for all symmetric
+## for all symmetric
 ## @tex
 ##  $n \times n$
 ## @end tex
 ## @ifnottex
-##  @math{n} by @math{n}
+## @math{n} by @math{n}
 ## @end ifnottex
-##  matrices
+## matrices
 ## @tex
 ##  $A$.
 ## @end tex
 ## @ifnottex
-##  @math{A}.
+## @math{A}.
 ## @end ifnottex
 ##
 ## See @nospell{Magnus and Neudecker} (1988), @cite{Matrix Differential