Reduce minor compilation warnings (#2058)

# Description
Reduces Rust compilation warnings. Remaining warnings related to
generated smart contracts will be fixed in
cowprotocol/ethcontract-rs#964

crates/driver/src/infra/solver/dto/auction.rs

@@ -266,7 +266,7 @@ struct Token {
 }
 
 // TODO Remove dead_code
-#[allow(dead_code)]
+#[allow(dead_code, clippy::enum_variant_names)]
 #[derive(Debug, Serialize)]
 #[serde(tag = "kind", rename_all = "lowercase")]
 enum Liquidity {

crates/orderbook/src/database/orders.rs

@@ -376,7 +376,7 @@ impl LimitOrderCounting for Postgres {
         let mut ex = self.pool.acquire().await?;
         Ok(database::orders::count_limit_orders_by_owner(
             &mut ex,
-            now_in_epoch_seconds().try_into().unwrap(),
+            now_in_epoch_seconds().into(),
             &ByteArray(owner.0),
         )
         .await?

crates/shared/src/price_estimation/trade_finder.rs

@@ -411,7 +411,7 @@ impl SettleOutput {
     /// Computes the actual [`Trade::out_amount`] based on the simulation.
     fn out_amount(&self, kind: OrderKind) -> Result<U256> {
         let balances = &self.queried_balances;
-        let balance_before = balances.get(0).context("no balance before settlement")?;
+        let balance_before = balances.first().context("no balance before settlement")?;
         let balance_after = balances.get(1).context("no balance after settlement")?;
         let out_amount = match kind {
             // for sell orders we track the buy_token amount which increases during the settlement

crates/shared/src/sources/uniswap_v3/event_fetching.rs

@@ -37,7 +37,7 @@ pub enum UniswapV3Event {
 impl ParseLog for UniswapV3Event {
     fn parse_log(log: RawLog) -> Result<Self, ExecutionError> {
         let standard_event: Option<Result<UniswapV3Event, ExecutionError>> =
-            log.topics.get(0).copied().map(|topic| match topic {
+            log.topics.first().copied().map(|topic| match topic {
                 H256(BURN_TOPIC) => Ok(UniswapV3Event::Burn(
                     log.clone().decode(
                         UniswapV3Pool::raw_contract()

crates/solver/src/driver.rs

@@ -540,13 +540,8 @@ impl Driver {
                 tracing::debug!(?hash, "settled transaction");
             }
 
-            self.logger.report_on_batch(
-                &(winning_solver, winning_settlement),
-                rated_settlements
-                    .into_iter()
-                    .map(|(solver, settlement)| (solver, settlement))
-                    .collect(),
-            );
+            self.logger
+                .report_on_batch(&(winning_solver, winning_settlement), rated_settlements);
         }
         // Happens after settlement submission so that we do not delay it.
         self.logger.report_simulation_errors(

crates/solvers/src/api/routes/solve/dto/auction.rs

@@ -144,6 +144,7 @@ struct Token {
     trusted: bool,
 }
 
+#[allow(clippy::enum_variant_names)]
 #[derive(Debug, Deserialize)]
 #[serde(tag = "kind", rename_all = "lowercase", deny_unknown_fields)]
 enum Liquidity {