Red black tree "remove" bug

[greenfork]

Order of removals breaks the tree, tests show the problem. I have no idea of when of whether I will be able to fix this, feel free to take over.

[greenfork]

Shorter bug reproduction:

1. Insert nodes 12, 15, 47, 50, 60
2. Remove 15

According to this visualisation before delete it should look like:

and after like this

but inspecting current implementation root is 47 and the deleted node 15 can be found as tree.root.?.right.?.left

[alexrp]

The intent with this repo is that the community can pick up these modules and turn them into proper, maintained packages. I would recommend doing exactly that with rb.zig and your fix here.