Use os.startfile() in WindowsViewer show_file()

[radarhere]

1. WindowsViewer currently uses start from get_command().

Pillow/src/PIL/ImageShow.py

Lines 133 to 135 in 87e7883

	def get_command(self, file: str, **options: Any) -> str:
	return (
	f'start "Pillow" /WAIT "{file}" '

However, a simpler method is to use os.startfile. This prevents injection. The temporary file can be removed after 20 seconds using os.remove(), like 8da8013

2. As for get_command(), direct injection can be prevented by raising an error if double quotes are used in file. This is valid, because Windows filenames cannot contain them..

3. Also in get_command(), variable expansion can be prevented by quoting percentages.