doc: miscellaneous documentation improvements * aspell-octave.en.pws: Add new words to spelling dictionary. * expr.txi: Use hyphens in "element-by-element" construction. * install.txi: Miscellaneous docstring improvements. * mk_undocumented_list: Update script. * xlim.m: Add ylim and zlim to function index. * data.cc: Add inf and nan to to function index. * file-io.cc: Add octave_tmp_file_name to function index. Expand docstring for SEEK_CUR and SEEK_END. * help.cc: Miscellaneous docstring improvements. * syscalls.cc: Improve docstrings for F_XXXX series of functions.

      subroutine fortsub (n, a, s)
      implicit none
      character*(*) s
      real*8 a(*)
      integer*4 i, n, ioerr
      do i = 1, n
        if (a(i) .eq. 0d0) then
          call xstopx ('fortsub: divide by zero')
        else
          a(i) = 1d0 / a(i)
        endif
      enddo
      write (unit = s, fmt = '(a,i3,a,a)', iostat = ioerr)
     $       'There are ', n,
     $       ' values in the input vector', char(0)
      if (ioerr .ne. 0) then
        call xstopx ('fortsub: error writing string')
      endif
      return
      end