ImageShow.show() for DisplayViewer doesn't work if no title is given

[csarn]

To reproduce the bug, just run ".show()" on any image object, while only having imagemagick's display viewer on the PATH.

from PIL import Image
Image.new('RGB', (10, 10)).show()

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.10/site-packages/PIL/Image.py", line 2259, in show
    _show(self, title=title)
  File "/usr/lib/python3.10/site-packages/PIL/Image.py", line 3233, in _show
    ImageShow.show(image, **options)
  File "/usr/lib/python3.10/site-packages/PIL/ImageShow.py", line 55, in show
    if viewer.show(image, title=title, **options):
  File "/usr/lib/python3.10/site-packages/PIL/ImageShow.py", line 79, in show
    return self.show_image(image, **options)
  File "/usr/lib/python3.10/site-packages/PIL/ImageShow.py", line 105, in show_image
    return self.show_file(self.save_image(image), **options)
  File "/usr/lib/python3.10/site-packages/PIL/ImageShow.py", line 212, in show_file
    subprocess.Popen(args)
  File "/usr/lib/python3.10/subprocess.py", line 966, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.10/subprocess.py", line 1775, in _execute_child
    self.pid = _posixsubprocess.fork_exec(
TypeError: expected str, bytes or os.PathLike object, not NoneType

The reason is that the DisplayViewer class just appends options["title"] to the argument list:

Pillow/src/PIL/ImageShow.py

Line 274 in 15dc291

args += ["-title", options["title"]]

But the default value for title is None:

Pillow/src/PIL/ImageShow.py

Line 51 in 15dc291

def show(image, title=None, **options):

[radarhere]

PR #6136 resolves this.