[1.x] Remove deprecated IntegrationTest config from doc

src/reference/02-DetailTopics/02-Configuration/14-Testing.md

@@ -248,81 +248,6 @@ to enable integration tests. The second shows how to define a customized
 test configuration. This allows you to define multiple types of tests
 per project.
 
-#### Integration Tests
-
-The following full build configuration demonstrates integration tests.
-
-```scala
-lazy val scalatest = "org.scalatest" %% "scalatest" % "$example_scalatest_version$"
-
-ThisBuild / organization := "com.example"
-ThisBuild / scalaVersion := "$example_scala_version$"
-ThisBuild / version      := "0.1.0-SNAPSHOT"
-
-lazy val root = (project in file("."))
-  .configs(IntegrationTest)
-  .settings(
-    Defaults.itSettings,
-    libraryDependencies += scalatest % "it,test"
-    // other settings here
-  )
-```
-
--   `configs(IntegrationTest)` adds the predefined integration test
-    configuration. This configuration is referred to by the name `it`. 
--   `settings(Defaults.itSettings)` adds compilation, packaging,
-    and testing actions and settings in the IntegrationTest
-    configuration.
--   `settings(libraryDependencies += scalatest % "it,test")` adds scalatest to both the
-    standard test configuration and the integration test configuration
-    it. To define a dependency only for integration tests, use "it" as
-    the configuration instead of "it,test".
-
-The standard source hierarchy is used:
-
--   `src/it/scala` for Scala sources
--   `src/it/java` for Java sources
--   `src/it/resources` for resources that should go on the integration
-    test classpath
-
-The standard testing tasks are available, but must be prefixed with
-`IntegrationTest/`. For example to run all integration tests:
-
-```
-> IntegrationTest/test
-```
-
-Or to run a specific test:
-
-```
-> IntegrationTest/testOnly org.example.AnIntegrationTest
-```
-
-Similarly the standard settings may be configured for the
-`IntegrationTest` configuration. If not specified directly, most
-`IntegrationTest` settings delegate to `Test` settings by default. For
-example, if test options are specified as:
-
-```scala
-Test / testOptions += ...
-```
-
-then these will be picked up by the `Test` configuration and in turn by
-the `IntegrationTest` configuration. Options can be added specifically
-for integration tests by putting them in the `IntegrationTest`
-configuration:
-
-```scala
-IntegrationTest / testOptions += ...
-```
-
-Or, use `:=` to overwrite any existing options, declaring these to be
-the definitive integration test options:
-
-```scala
-IntegrationTest / testOptions := Seq(...)
-```
-
 #### Custom test configuration
 
 The previous example may be generalized to a custom test configuration.