See also:
https://wiki.octave.org/Commit_message_guidelines

pushed a doc change to http://hg.savannah.gnu.org/hgweb/octave/rev/0cb3f48da9da
that changes array to vector and matrix as appropriate in the docstring.

This appears to be a compatibility concern, not sure if this is from a change in matlab behavior:

Matlab 2021b:

abc = ['a1'; 'a2'; 'a3'];

issorted (abc)
ans =
  logical
   1

issorted({abc})
ans =
  logical
   1

abc = ['a1'; 'a3'; 'a2'];

issorted (abc)
ans =
  logical
   0

issorted({abc})
ans =
  logical
   1

abc = ['a1'; 'b2'; 'a3'];

issorted (abc)
ans =
  logical
   0

issorted({abc})
ans =
  logical
   1

I included cellstrings because it seemed to be the only way octave would try to process it:
Octave 7.0.1 (hg id: d00ae0ad8f89)

abc = ['a1'; 'a2'; 'a3'];

issorted(abc)
error: issorted: needs a vector

issorted({abc})
warning: multi-row character matrix converted to a string, only
the first row is used
ans = 1

abc = ['a1'; 'a3'; 'a2'];

issorted(abc)
error: issorted: needs a vector

issorted({abc})
warning: multi-row character matrix converted to a string, only
the first row is used
ans = 1

abc = ['a1'; 'b2'; 'a3'];

issorted(abc)
error: issorted: needs a vector

issorted({abc})
warning: multi-row character matrix converted to a string, only
the first row is used
ans = 1

So matlab appears to have no issues checking sorting on a char array, while octave does.  Matlab also appears to look at a char array in a cell as a single unit for sorting, whereas octave sees it as a string array, but then aborts checking for sorting anyway.