failed: TimeoutDirectivesExamplesSpec - should be configurable in routing layer despite infinite initial value of request-timeout

https://github.com/akka/akka-http/actions/runs/5470906217/jobs/9961496867#step:7:5078

```scala
- should be configurable in routing layer despite infinite initial value of request-timeout *** FAILED *** (3 seconds, 272 milliseconds)
[info] java.util.concurrent.TimeoutException: Future timed out after [3 seconds]
[info] at scala.concurrent.impl.Promise$DefaultPromise.tryAwait0(Promise.scala:248)
[info] at scala.concurrent.impl.Promise$DefaultPromise.result(Promise.scala:261)
[info] at scala.concurrent.Await$.$anonfun$result$1(package.scala:201)
[info] at scala.concurrent.BlockContext$DefaultBlockContext$.blockOn(BlockContext.scala:62)
[info] at scala.concurrent.Await$.result(package.scala:124)
[info] at akka.http.scaladsl.testkit.RouteTest$TildeBangArrow$$anon$2.apply(RouteTest.scala:201)
[info] at akka.http.scaladsl.testkit.RouteTest$TildeBangArrow$$anon$2.apply(RouteTest.scala:196)
[info] at akka.http.scaladsl.testkit.RouteTest$WithTransformation2.$tilde$bang$greater(RouteTest.scala:141)
[info] at docs.http.scaladsl.server.directives.TimeoutDirectivesExamplesSpec.$anonfun$new$2(TimeoutDirectivesExamplesSpec.scala:47)
[info] at org.scalatest.OutcomeOf.outcomeOf(OutcomeOf.scala:85)
[info] at org.scalatest.OutcomeOf.outcomeOf$(OutcomeOf.scala:83)
[info] at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104)
[info] at org.scalatest.Transformer.apply(Transformer.scala:22)
[info] at org.scalatest.Transformer.apply(Transformer.scala:20)
[info] at org.scalatest.wordspec.AnyWordSpecLike$$anon$3.apply(AnyWordSpecLike.scala:1227)
[info] at akka.http.impl.util.WithLogCapturing.$anonfun$withFixture$1(WithLogCapturing.scala:49)
[info] at akka.testkit.EventFilter.intercept(TestEventListener.scala:119)
[info] at akka.http.impl.util.WithLogCapturing.withFixture(WithLogCapturing.scala:47)
[info] at akka.http.impl.util.WithLogCapturing.withFixture$(WithLogCapturing.scala:34)
[info] at akka.http.scaladsl.server.RoutingSpec.withFixture(RoutingSpec.scala:25)
[info] at org.scalatest.wordspec.AnyWordSpecLike.invokeWithFixture$1(AnyWordSpecLike.scala:1225)
[info] at org.scalatest.wordspec.AnyWordSpecLike.$anonfun$runTest$1(AnyWordSpecLike.scala:1237)
[info] at org.scalatest.SuperEngine.runTestImpl(Engine.scala:306)

```

Start with docs.http.scaladsl.server.directives.TimeoutDirectivesExamplesSpec.scala at line 47 and reproduce the failing test from the reported CI run. Read the surrounding timeout-directive example and routing test setup; done means the test no longer times out while still verifying that request-timeout can be configured in the routing layer.

Written by the indexing model from the issue text.