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/handle_alias.cpp

@@ -11,19 +11,19 @@
 namespace Carbon::Check {
 
 auto HandleAliasIntroducer(Context& context,
-                           Parse::AliasIntroducerId /*parse_node*/) -> bool {
+                           Parse::AliasIntroducerId /*node_id*/) -> bool {
   context.decl_state_stack().Push(DeclState::Alias);
   context.decl_name_stack().PushScopeAndStartName();
   return true;
 }
 
 auto HandleAliasInitializer(Context& /*context*/,
-                            Parse::AliasInitializerId /*parse_node*/) -> bool {
+                            Parse::AliasInitializerId /*node_id*/) -> bool {
   return true;
 }
 
-auto HandleAlias(Context& context, Parse::AliasId /*parse_node*/) -> bool {
-  auto [expr_node, expr_id] = context.node_stack().PopExprWithParseNode();
+auto HandleAlias(Context& context, Parse::AliasId /*node_id*/) -> bool {
+  auto [expr_node, expr_id] = context.node_stack().PopExprWithNodeId();
 
   auto name_context = context.decl_name_stack().FinishName();
 
@@ -48,20 +48,20 @@ auto HandleAlias(Context& context, Parse::AliasId /*parse_node*/) -> bool {
     // TODO: Look into handling `false`, this doesn't do it right now because it
     // sees a value instruction instead of a builtin.
     alias_id = context.AddInst(
-        {name_context.parse_node,
+        {name_context.node_id,
          SemIR::BindAlias{context.insts().Get(expr_id).type_id(), bind_name_id,
                           expr_id}});
   } else if (auto inst = context.insts().TryGetAs<SemIR::NameRef>(expr_id)) {
     // Pass through name references, albeit changing the name in use.
     alias_id = context.AddInst(
-        {name_context.parse_node,
+        {name_context.node_id,
          SemIR::BindAlias{inst->type_id, bind_name_id, inst->value_id}});
   } else {
     CARBON_DIAGNOSTIC(AliasRequiresNameRef, Error,
                       "Alias initializer must be a name reference.");
     context.emitter().Emit(expr_node, AliasRequiresNameRef);
     alias_id =
-        context.AddInst({name_context.parse_node,
+        context.AddInst({name_context.node_id,
                          SemIR::BindAlias{SemIR::TypeId::Error, bind_name_id,
                                           SemIR::InstId::BuiltinError}});
   }