quiver: Improve plotting with non-float numeric inputs (bug #59695) * scripts/plot/draw/private/__quiver__.m: Change firstnonnumeric check to look for char instead of numeric to allow for logical inputs. Recast all inputs up to firstnonnumeric as doubles. Check if firstnonnumeric element is 'off' and if so set scale factor to 0 and increment firstnonnumeric. * scripts/plot/draw/quiver.m: Update docstring to include scaling factor option 'off'. Add BIST for int and logical input types. * scripts/plot/draw/quiver3.m: Update docstring to include scaling factor option 'off'. Add BISTs for too-few inputs. * etc/NEWS.9.md: Appended details of changes to quiver note under General Improvements and noted it also applies to quiver3.

Things to do before making a release:

  * Update the version number and release date in configure.ac.

  * Update the OCTAVE_API_VERSION number in configure.ac.

  * Update version number and release year in CITATION.

  * Update the etc/NEWS.N.md file corresponding to the major release
    number N.  Include release date in Summary header.

  * Update the NEWS-<VERSION>.html, index.in, news.in, and download.in
    files for the web site.

  * Copy tarballs to ftp.gnu.org.

  * Post a release announcement to the help@octave.org and
    info-gnu@gnu.org lists.

  * Update https://wiki.octave.org/Release_History page.