Make votingapi_tokens submodule D9 compatible

There are no deprecations, so all that is really required is a declaration in the info.yml file that this module is D9 compatible. This patch adds that declaration.

And as long as we're doing this, I think it would be good to correct the coding standards problems and also fixes a minor problem from a static analysis with PHPStan.

There are just a few coding standards fixes, and the PHPStan error is that in hook_token_info(), the $types and $tokens variables need to be initialized because they might not be defined before they are returned.

With these fixes, votingapi_tokens will be both D9 compatible and free of coding standards problems. Then we can move on to making the main module D9 compatible.