genjavadoc: update 0.16 -> 0.17 (#30121)

To get the fix for 'rangepos', which is becoming the default with 2.13.5

project/Doc.scala

@@ -185,7 +185,7 @@ object BootstrapGenjavadoc extends AutoPlugin {
 
   override lazy val projectSettings = UnidocRoot.CliOptions.genjavadocEnabled
     .ifTrue(Seq(
-      unidocGenjavadocVersion := "0.16",
+      unidocGenjavadocVersion := "0.17",
       scalacOptions in Compile ++= Seq("-P:genjavadoc:fabricateParams=false", "-P:genjavadoc:suppressSynthetic=false")))
     .getOrElse(Nil)
 }