Overhaul input validation of sparse() function. * sparse.cc (Fsparse): Decode input type and identify floating point inputs. If input is of single type, emit new warning "Octave:sparse:double-conversion". If input is neither floating point or logical, then call err_wrong_type_arg() for pretty error message. Rename temporary variable 'k' to "argidx" for clarity. New temporary variable "arg" to increase readability of code. Add FIXME note about unreachable code due to behavior of get_dimensions(). * sparse.cc (Fissparse): Turn off warning about double-conversion temporarily for test which has single input. * warning_ids.m: Add description for new warning ID "Octave:sparse:double-conversion". * mk-sparse-tst.sh: Redo BIST tests for sparse() construction.

To cite GNU Octave in publications use:

  John W. Eaton, David Bateman, Søren Hauberg, Rik Wehbring (2023).
  GNU Octave version 8.2.0 manual: a high-level interactive language for
  numerical computations.
  URL https://www.gnu.org/software/octave/doc/v8.2.0/

A BibTeX entry for LaTeX users is:

  @manual{,
    title     = {{GNU Octave} version 8.2.0 manual: a high-level interactive language for numerical computations},
    author    = {John W. Eaton and David Bateman and S{\o}ren Hauberg and Rik Wehbring},
    year      = {2023},
    url       = {https://www.gnu.org/software/octave/doc/v8.2.0/},
  }

We have invested a lot of time and effort in creating GNU Octave, please
cite it when using it.  See also 'citation pkgname' for citing Octave
packages.