[TwigBundle] Describe the new behaviour of twig.cache config

[Okhoshi]

Update the description of the twig.cache config to follow the changes implemented in symfony/symfony#54384.

Fixes #20948

cc @alexandre-daubois

[OskarStark]

Please add a versionadded directive here, thanks

[GromNaN]

I've rewritten this paragraph trying to simplify the wording and logic.
"not enabled" is "disabled"

Suggested change

	Set this option to the path where the cache should be stored. If set to
	``true``, the cache is stored in ``%kernel.cache_dir%/twig``. However, if the
	``auto_reload`` option is not enabled and ``%kernel.build_dir`` is configured
	to be different than ``%kernel.cache_dir``, the cache is stored in
	``%kernel.build_dir%/twig``.
	Specify the path where the cache should be stored. If set to `true`, the cache
	defaults to `%kernel.cache_dir%/twig`. However, if the `auto_reload` option is
	disabled and `%kernel.build_dir%` is different from `%kernel.cache_dir%`,
	the cache will instead be stored in `%kernel.build_dir%/twig`.