fix link to websocket example code, akka#19964
+doc introduce algolia search box
Version 2.4.2
Version 2.4.2-RC3
Version 2.4.2-RC2
Version akka-stream-and-http-experimental-2.0.3
Version 2.4.2-RC1
Version akka-stream-and-http-experimental-2.0.2
Merge pull request akka#19396 from akka/wip-18948-eagerComplete-RK akka#18948 add eagerComplete parameter to FlowOps.merge