refactor: introduced Diff and FileChange VOs

[NickSdot]

Preflight. Adds two DTOs and extracts some logic from the sniffer. Not working with arrays made things much easier. Test are so that we have as little diff churn as possible and the assertions are goal-wise the same.

DiffParserTest has a small helper addition lineNumbersByFile() which I marked myself as todo; not optimal to merge todos but I need to keep things a bit organised if I want to get the fixer PR diff smaller. When fixers are merged I will follow up with the various todos.

[NickSdot]

@jordikroon I had my first risky coverage CI failure here. Adding every class as an attribute, plus having its import, seems quite excessive. 😅 Are we fine with grouped attributes + FQN?

#[UsesClass(\DocbookCS\Source\File::class), UsesClass(\DocbookCS\Source\Line::class)]
finalclass SniffRunnerTest extends TestCase {
/// ...
}

[jordikroon]

@jordikroon I had my first risky coverage CI failure here. Adding every class as an attribute, plus having its import, seems quite excessive. 😅 Are we fine with grouped attributes + FQN?

#[UsesClass(\DocbookCS\Source\File::class), UsesClass(\DocbookCS\Source\Line::class)]
final class SniffRunnerTest extends TestCase {
/// ...
}

It is excessive and long, however I assume there is a high chance the class is used in the test directly. For that reason it's better to not use the FQNS. Otherwise a portion will be inconstant. Some IDE's do collapse the list of imported namespaces though.

[NickSdot]

My bad that #30 and #31 didn't have the "depends on" in their description. Not merging them in order caused this one to conflict. Conflicts are resolved now, and the stacked 10 branches are rebased.

[jordikroon]

Thanks. And as discussed you will handle the feedback in follow up MRs.

[NickSdot]

Thanks. And as discussed you will handle the feedback in follow up MRs.

Yups. Both should be handled/obsolete. If I missed something let me know.

Will rebase now, then un-draft the next one.