[chore][GraphQL/Limits] Standardise query_limits_checker file order (M…

…ystenLabs#18663)

## Description

This is a file order change only, with no other meaningful changes. It
standardises the order to:

- Constants
- Types
- Impls
- Trait Impls
- Free functions

## Test plan

CI

## Stack
- MystenLabs#18660
- MystenLabs#18661 
- MystenLabs#18662 

---

## Release notes

Check each box that your changes affect. If none of the boxes relate to
your changes, release notes aren't required.

For each box you select, include information after the relevant heading
that describes the impact of your changes that a user might notice and
any actions they must take to implement updates.

- [ ] Protocol: 
- [ ] Nodes (Validators and Full nodes): 
- [ ] Indexer: 
- [ ] JSON-RPC: 
- [ ] GraphQL: 
- [ ] CLI: 
- [ ] Rust SDK:

crates/sui-graphql-rpc/src/extensions/query_limits_checker.rs

@@ -23,9 +23,16 @@ use tokio::sync::Mutex;
 use tracing::info;
 use uuid::Uuid;
 
+pub(crate) const CONNECTION_FIELDS: [&str; 2] = ["edges", "nodes"];
+
 /// Extension factory for adding checks that the query is within configurable limits.
 pub(crate) struct QueryLimitsChecker;
 
+#[derive(Debug, Default)]
+struct QueryLimitsCheckerExt {
+    validation_result: Mutex<Option<ValidationRes>>,
+}
+
 /// Only display usage information if this header was in the request.
 pub(crate) struct ShowUsage;
 
@@ -39,13 +46,13 @@ struct ValidationRes {
     query_payload: u32,
 }
 
-#[derive(Debug, Default)]
-struct QueryLimitsCheckerExt {
-    validation_result: Mutex<Option<ValidationRes>>,
+#[derive(Debug)]
+struct ComponentCost {
+    pub input_nodes: u32,
+    pub output_nodes: u32,
+    pub depth: u32,
 }
 
-pub(crate) const CONNECTION_FIELDS: [&str; 2] = ["edges", "nodes"];
-
 impl ShowUsage {
     pub(crate) fn name() -> &'static HeaderName {
         &LIMITS_HEADER
@@ -60,25 +67,6 @@ impl ExtensionFactory for QueryLimitsChecker {
     }
 }
 
-#[derive(Debug)]
-struct ComponentCost {
-    pub input_nodes: u32,
-    pub output_nodes: u32,
-    pub depth: u32,
-}
-
-impl std::ops::Add for ComponentCost {
-    type Output = Self;
-
-    fn add(self, rhs: Self) -> Self::Output {
-        Self {
-            input_nodes: self.input_nodes + rhs.input_nodes,
-            output_nodes: self.output_nodes + rhs.output_nodes,
-            depth: self.depth + rhs.depth,
-        }
-    }
-}
-
 #[async_trait::async_trait]
 impl Extension for QueryLimitsCheckerExt {
     async fn request(&self, ctx: &ExtensionContext<'_>, next: NextRequest<'_>) -> Response {
@@ -210,6 +198,18 @@ impl Extension for QueryLimitsCheckerExt {
     }
 }
 
+impl std::ops::Add for ComponentCost {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        Self {
+            input_nodes: self.input_nodes + rhs.input_nodes,
+            output_nodes: self.output_nodes + rhs.output_nodes,
+            depth: self.depth + rhs.depth,
+        }
+    }
+}
+
 /// Parse the selected fields in one operation and check if it conforms to configured limits.
 fn analyze_selection_set(
     limits: &Limits,