Rename parse_node -> node_id (#3760)

This was previously discussed at
https://discord.com/channels/655572317891461132/655578254970716160/1209975051588210729.
I'm initiating this mainly because we typically use "id" suffixes to
indicate an `IdBase` being passed around and the non-id suffix of
`parse_node` suggests at it carrying more data than it actually does.
There used to be more reason for avoiding `node_id` because
`SemIR::InstId` used to be named `NodeId`, but that's no longer
necessary. As a consequence, I'd like to rename `parse_node` to more
precisely reflect its type.

In full, this is doing:

```
parse_node_kind -> node_kind
parse_node -> node_id
ParseNodeCategory -> NodeCategory
ParseNodeKind -> NodeKind
ParseNode -> NodeId
```

This is primarily in check and sem_ir, but with some `parse_node_kind`
references in parse too.

Pluralization is consistent with name forms on both sides, so that
wasn't part of my replacements.

toolchain/check/eval.cpp

@@ -302,7 +302,7 @@ auto TryEvalInst(Context& context, SemIR::InstId inst_id, SemIR::Inst inst)
             if (!int_bound) {
               // TODO: Permit symbolic array bounds. This will require fixing
               // callers of `GetArrayBoundValue`.
-              context.TODO(context.insts().GetParseNode(bound_id),
+              context.TODO(context.insts().GetNodeId(bound_id),
                            "symbolic array bound");
               return false;
             }