docs(payload): fix typos and incorrect references in comments (#20771)

Signed-off-by: Hwangjae Lee <meetrick@gmail.com>

crates/payload/basic/src/lib.rs

@@ -297,7 +297,7 @@ impl Default for BasicPayloadJobGeneratorConfig {
 /// resolved or the deadline is reached, or until the built payload is marked as frozen:
 /// [`BuildOutcome::Freeze`]. Once a frozen payload is returned, no additional payloads will be
 /// built and this future will wait to be resolved: [`PayloadJob::resolve`] or terminated if the
-/// deadline is reached..
+/// deadline is reached.
 #[derive(Debug)]
 pub struct BasicPayloadJob<Tasks, Builder>
 where

crates/payload/basic/src/metrics.rs

@@ -2,7 +2,7 @@
 
 use reth_metrics::{metrics::Counter, Metrics};
 
-/// Transaction pool metrics
+/// Payload builder metrics
 #[derive(Metrics)]
 #[metrics(scope = "payloads")]
 pub(crate) struct PayloadBuilderMetrics {