fix old `in` syntax

main/src/main/scala/sbt/Defaults.scala

@@ -700,8 +700,8 @@ object Defaults extends BuildCommon {
     pluginCrossBuild / sbtBinaryVersion := binarySbtVersion(
       (pluginCrossBuild / sbtVersion).value
     ),
-    // Use (sbtVersion in pluginCrossBuild) to pick the sbt module to depend from the plugin.
-    // Because `sbtVersion in pluginCrossBuild` can be scoped to project level,
+    // Use (pluginCrossBuild / sbtVersion) to pick the sbt module to depend from the plugin.
+    // Because `pluginCrossBuild / sbtVersion` can be scoped to project level,
     // this setting needs to be set here too.
     pluginCrossBuild / sbtDependency := {
       val app = appConfiguration.value

main/src/main/scala/sbt/Keys.scala

@@ -229,7 +229,7 @@ object Keys {
   val sbtPlugin = settingKey[Boolean]("If true, enables adding sbt as a dependency and auto-generation of the plugin descriptor file.").withRank(BMinusSetting)
   val isMetaBuild = settingKey[Boolean]("If true, this is a metabuild, a project inside project/ directory, and sbt is added to the classpath.").withRank(DSetting)
   val reresolveSbtArtifacts = settingKey[Boolean]("If true, include sbt into the metabuild dependency graph. Otherwise reuse the artifacts resolved by the launcher on startup.").withRank(DSetting)
-  val pluginCrossBuild = taskKey[Unit]("Dummy task to scope `sbtVersion in pluginCrossBuild`, which gets used for plugin compilation.")
+  val pluginCrossBuild = taskKey[Unit]("Dummy task to scope `pluginCrossBuild / sbtVersion`, which gets used for plugin compilation.")
   val crossSbtVersions = settingKey[Seq[String]]("The versions of Sbt used when cross-building an sbt plugin.")
   val printWarnings = taskKey[Unit]("Shows warnings from compilation, including ones that weren't printed initially.").withRank(BPlusTask)
   val fileInputOptions = settingKey[Seq[String]]("Options that take file input, which may invalidate the cache.").withRank(CSetting)

main/src/main/scala/sbt/PluginCross.scala

@@ -46,7 +46,7 @@ private[sbt] object PluginCross {
       case (state, (version, command)) =>
         val x = Project.extract(state)
         import x._
-        state.log.info(s"Setting `sbtVersion in pluginCrossBuild` to $version")
+        state.log.info(s"Setting `pluginCrossBuild / sbtVersion` to $version")
         val add = List(GlobalScope / pluginCrossBuild / sbtVersion :== version) ++
           List(scalaVersion := scalaVersionSetting.value) ++
           inScope(GlobalScope.copy(project = Select(currentRef)))(

main/src/main/scala/sbt/internal/CommandStrings.scala

@@ -407,7 +407,7 @@ $SwitchCommand [<scala-version>=]<scala-home>[!] [-v] [<command>]
   Runs <command> for each sbt version specified for cross-building.
 
   For each string in `crossSbtVersions` in the current project, this command sets the
-  `sbtVersion in pluginCrossBuild` of all projects to that version, reloads the build,
+  `pluginCrossBuild / sbtVersion` of all projects to that version, reloads the build,
   and executes <command>.  When finished, it reloads the build with the original
   Scala version.
 
@@ -418,7 +418,7 @@ $SwitchCommand [<scala-version>=]<scala-home>[!] [-v] [<command>]
     s"""$PluginSwitchCommand <sbt-version> [<command>]
   Changes the sbt version and runs a command.
 
-  Sets the `sbtVersion in pluginCrossBuild` of all projects to <sbt-version> and
+  Sets the `pluginCrossBuild / sbtVersion` of all projects to <sbt-version> and
   reloads the build. If <command> is provided, it is then executed.
 
   See also `help $CrossCommand`

sbt-app/src/sbt-test/project1/cross-plugins-defaults/build.sbt

@@ -25,7 +25,7 @@ def mkCheck(scalaBinV: String, sbtBinVer: String, sbtVerPrefix: String) = Def.ta
     scalaBinaryVersion.value == scalaBinV,
     s"Wrong Scala binary version: ${scalaBinaryVersion.value}"
   )
-  assert(crossV startsWith sbtVerPrefix, s"Wrong `sbtVersion in pluginCrossBuild`: $crossV")
+  assert(crossV startsWith sbtVerPrefix, s"Wrong `pluginCrossBuild / sbtVersion`: $crossV")
 
   val ur = update.value
   val cr = ur.configuration(Compile).get