tarfile, zipfile, and shutil documentation should mention zstd compression

[randomdude999]

Documentation

Python 3.14 added zstd compression support in the standard library, and tarfile, zipfile and shutil can now use it.

• The documentation of tarfile.open() should be updated to mention zstd compression.
• Documentation of shutil.make_archive(), shutil.get_archive_formats(), shutil.unpack_archive(), and shutil.get_unpack_formats() should be updated.
• zipfile documentation should mention the ZIP_ZSTANDARD flag.

Linked PRs

• gh-135252: Document Zstandard integration across zipfile, shutil, and tarfile #135311

[StanFromIreland]

cc @emmatyping

[emmatyping]

Thanks, will make PR today or tomorrow for this.