Update to Rust 1.81.0, fix clippy suggestions (#610)

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-->

### What

Upgrade to Rust 1.81.0, fix clippy lint suggestions.

### How

Update `rust-toolchain.yaml`

crates/query-engine/execution/src/mutation.rs

@@ -30,9 +30,8 @@ pub async fn execute(
         .await;
     let mut connection = acquisition_timer
         .complete_with(connection_result)
-        .map_err(|err| {
+        .inspect_err(|_err| {
             metrics.error_metrics.record_connection_acquisition_error();
-            err
         })?;
 
     let query_timer = metrics.time_query_execution();
@@ -195,13 +194,11 @@ pub async fn explain(
                     internal.visibility = "user",
                 ))
                 .await;
-            let mut connection =
-                acquisition_timer
-                    .complete_with(connection_result)
-                    .map_err(|err| {
-                        metrics.error_metrics.record_connection_acquisition_error();
-                        err
-                    })?;
+            let mut connection = acquisition_timer
+                .complete_with(connection_result)
+                .inspect_err(|_err| {
+                    metrics.error_metrics.record_connection_acquisition_error();
+                })?;
 
             tracing::info!(
                 generated_sql = query_sql.sql,

crates/query-engine/execution/src/query.rs

@@ -33,9 +33,8 @@ pub async fn execute(
         .await;
     let mut connection = acquisition_timer
         .complete_with(connection_result)
-        .map_err(|err| {
+        .inspect_err(|_err| {
             metrics.error_metrics.record_connection_acquisition_error();
-            err
         })?;
 
     let query_timer = metrics.time_query_execution();
@@ -83,13 +82,11 @@ pub async fn explain(
                     internal.visibility = "user",
                 ))
                 .await;
-            let mut connection =
-                acquisition_timer
-                    .complete_with(connection_result)
-                    .map_err(|err| {
-                        metrics.error_metrics.record_connection_acquisition_error();
-                        err
-                    })?;
+            let mut connection = acquisition_timer
+                .complete_with(connection_result)
+                .inspect_err(|_err| {
+                    metrics.error_metrics.record_connection_acquisition_error();
+                })?;
 
             for statement in plan.pre {
                 execute_statement(&mut connection, &statement).await?;

flake.nix

@@ -7,7 +7,6 @@
 
     crane = {
       url = "github:ipetkov/crane";
-      inputs.nixpkgs.follows = "nixpkgs";
     };
 
     rust-overlay = {

rust-toolchain.toml

@@ -1,4 +1,4 @@
 [toolchain]
-channel = "1.80.1"
+channel = "1.81.0"
 profile = "default"  # see https://rust-lang.github.io/rustup/concepts/profiles.html
 components = ["rust-analyzer", "rust-src"]  # see https://rust-lang.github.io/rustup/concepts/components.html