Add redirects to the equality checks for nodes.

[dualspiral]

Redirects are added as reference equality checks rather than standard object equality checks because of a stack overflow that can occur if a redirect is to a parent of the current node. If two nodes are redirected to two different nodes that otherwise look the same, then they will not be equal, which is fine because if one of the nodes gains a new child then they won't be equal any more - so I think this is a sensible check to have.

If there is an alternative idea I'd be open to that too - as long as redirects are included in the equality contract somehow - this is just what I think is the most sensible thing to do.

Test included to demonstrate the change.

(See SpongePowered/Sponge#3356 for more info on how this is affecting us.)

[liach]

As far as I can see, the argument command nodes can be distinguished by name.

brigadier/src/main/java/com/mojang/brigadier/tree/ArgumentCommandNode.java

Line 105 in cf754c4

if (!name.equals(that.name)) return false;

Afaik, the name is only used in rendering in command suggestions, like that on the client.
🤔 What prevents you from choosing different names for the command nodes to send to the client to distinguish these nodes?

[dualspiral]

Not for two literals that have the same name/literal but different redirects (think two literals in different commands that redirect back, such as an -f flag).

[chixvv1]

This fixes MC-137380