fleetd #737 unit 3: name the resolving accessor in LeadRollover's javadoc

The heartbeat loop now resolves its nudge target through
PrimaryRegistry#currentPrimaryTerminal(), so the sentence describing what a
background loop with no caller uses named the raw accessor instead.

fleetd/src/main/java/dev/ltms/fleet/lead/LeadRollover.java

@@ -93,7 +93,7 @@ import java.util.function.Supplier;
  *
  * <p><strong>Identity is resolved by the caller, never looked up here — a second fleetd #480
  * correction.</strong> The first version resolved the pane to clear via {@code
- * PrimaryRegistry#primaryTerminal()}. That is correct for a background loop with no caller (see
+ * PrimaryRegistry#currentPrimaryTerminal()}. That is correct for a background loop with no caller (see
  * {@code dev.ltms.fleet.msg.LeadHeartbeatLoop}), but wrong here and a violation of this project's
  * own charter invariant 3 — "identity comes from the connection, never an argument." This daemon
  * can hold more than one labelled lead tab (see {@code LeadLauncher}'s fleetd #359 two-reading