Remove words such as simply and obviously from docs (#25095)

* One does not "simply"

* It's not obvious

* It's not really _that_ easily done

* Basically is basically a useless word

* Of course - if you already know how things work you wouldn't be reading the docs

* Clearly is maybe not so clear for everyone

* Just was just a bit harder as there are some uses that are just

akka-docs/src/test/scala/docs/serialization/SerializationDocSpec.scala

@@ -214,12 +214,12 @@ package docs.serialization {
       // (beneath toBinary)
       val identifier: String = Serialization.serializedActorPath(theActorRef)
 
-      // Then just serialize the identifier however you like
+      // Then serialize the identifier however you like
 
       // Deserialize
       // (beneath fromBinary)
       val deserializedActorRef = extendedSystem.provider.resolveActorRef(identifier)
-      // Then just use the ActorRef
+      // Then use the ActorRef
       //#actorref-serializer
 
       //#external-address

akka-docs/src/test/scala/docs/stream/GraphStageDocSpec.scala

@@ -427,7 +427,7 @@ class GraphStageDocSpec extends AkkaSpec {
               promise.success(elem)
               push(out, elem)
 
-              // replace handler with one just forwarding
+              // replace handler with one that only forwards elements
               setHandler(in, new InHandler {
                 override def onPush(): Unit = {
                   push(out, grab(in))

akka-docs/src/test/scala/docs/stream/cookbook/RecipeCollectingMetrics.scala

@@ -72,7 +72,7 @@ class RecipeCollectingMetrics extends RecipeSpec {
       //        the counter stream and store the final value, and also repeat this final value if no update is received between
       //      metrics collection rounds.
       //
-      //        To finish the recipe, we simply use :class:`ZipWith` to trigger reading the latest value from the ``currentLoad``
+      //        To finish the recipe, we use :class:`ZipWith` to trigger reading the latest value from the ``currentLoad``
       //        stream whenever a new ``Tick`` arrives on the stream of ticks, ``reportTicks``.
       //
       //        .. includecode:: ../code/docs/stream/cookbook/RecipeCollectingMetrics.scala#periodic-metrics-collection