`procgen` changes to support code blocks (zircote#1742)

Resolve class names to refs in `Discriminator::mapping` (zircote#1736)

Improve docblocks (zircote#1723)

Type-hhint actual string values where possible and also
fix attribute operation parameter type bug (add missing type mapping)

Consider `type` might be an array when checking `Item` parent type (z…

…ircote#1708)

Remove the deprecated `ProcessorInterface` (zircote#1696)

Initialize Generator::$context (zircote#1692)

Update tooling and dependency versions (zircote#1691)

Update PHP requirements (zircote#1687)

Fix readme links (zircote#1665)

Allow nesting of `Attachable` annotations (zircote#1663)