docs(nextjs): Correct what a navigation during the pageload wait does

The Next.js routing instrumentation never flags a navigation as a redirect,
so a navigation during the wait ends the pageload like any pageload it
interrupts and starts its own trace, as it does today.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Author: chargome

packages/nextjs/src/client/browserTracingIntegration.ts

@@ -43,8 +43,9 @@ export function browserTracingIntegration(
       }
 
       // Registered before the browser tracing integration's own handler, which creates the navigation
-      // span: a pageload that is still waiting for its trace meta tag has to exist by then so the
-      // navigation can be filed as its redirect.
+      // span: a pageload that is still waiting for its trace meta tag has to exist by then, so the
+      // handler ends it like any pageload a navigation interrupts. Started later, the pageload would
+      // end the navigation span instead.
       if (instrumentPageLoad) {
         client.on('startNavigationSpan', settlePendingPageloadWait);
       }

packages/nextjs/src/client/routing/appRouterRoutingInstrumentation.ts

@@ -108,8 +108,8 @@ let pendingPageloadWait: TraceMetaTagWait | undefined;
 
 /**
  * Starts a pageload that is still waiting for its trace meta tag with a fresh trace. Called when a
- * navigation starts, before the navigation span is created, so that the navigation is filed as a
- * redirect of this pageload rather than becoming the only record of the visit.
+ * navigation starts, before the navigation span is created, so the navigation ends the pageload like
+ * any pageload it interrupts, and the pageload is still recorded.
  */
 export function settlePendingPageloadWait(): void {
   pendingPageloadWait?.giveUp();