#39 - trailing commas for match expressions

[krzysztofrewak]

With this pull request this:

return match ($i) {
    1 => 1,
    2 => 3,
    default => 0
};

will be transformed to this:

return match ($i) {
    1 => 1,
    2 => 3,
    default => 0,
};

This should finally close #39.