Use current links to JUnit documentation

Closes gh-35892

framework-docs/modules/ROOT/pages/languages/kotlin/spring-projects-in.adoc

@@ -319,7 +319,7 @@ progresses.
 == Testing
 
 This section addresses testing with the combination of Kotlin and Spring Framework.
-The recommended testing framework is https://junit.org/junit5/[JUnit] along with
+The recommended testing framework is https://junit.org/[JUnit] along with
 https://mockk.io/[Mockk] for mocking.
 
 NOTE: If you are using Spring Boot, see

framework-docs/modules/ROOT/pages/testing/annotations/integration-junit-jupiter.adoc

@@ -187,7 +187,7 @@ default mode may be set via the
 xref:appendix.adoc#appendix-spring-properties[`SpringProperties`] mechanism.
 
 The default mode may also be configured as a
-https://junit.org/junit5/docs/current/user-guide/#running-tests-config-params[JUnit Platform configuration parameter].
+https://docs.junit.org/current/user-guide/#running-tests-config-params[JUnit Platform configuration parameter].
 
 If the `spring.test.constructor.autowire.mode` property is not set, test class
 constructors will not be automatically autowired.

framework-docs/modules/ROOT/pages/testing/testcontext-framework/support-classes.adoc

@@ -22,7 +22,7 @@ TestNG:
 * Dependency injection for test constructors, test methods, and test lifecycle callback
   methods. See xref:testing/testcontext-framework/support-classes.adoc#testcontext-junit-jupiter-di[Dependency
   Injection with the `SpringExtension`] for further details.
-* Powerful support for link:https://junit.org/junit5/docs/current/user-guide/#extensions-conditions[conditional
+* Powerful support for link:https://docs.junit.org/current/user-guide/#extensions-conditions[conditional
   test execution] based on SpEL expressions, environment variables, system properties,
   and so on. See the documentation for `@EnabledIf` and `@DisabledIf` in
   xref:testing/annotations/integration-junit-jupiter.adoc[Spring JUnit Jupiter Testing Annotations]
@@ -160,7 +160,7 @@ for further details.
 === Dependency Injection with the `SpringExtension`
 
 The `SpringExtension` implements the
-link:https://junit.org/junit5/docs/current/user-guide/#extensions-parameter-resolution[`ParameterResolver`]
+link:https://docs.junit.org/current/user-guide/#extensions-parameter-resolution[`ParameterResolver`]
 extension API from JUnit Jupiter, which lets Spring provide dependency injection for test
 constructors, test methods, and test lifecycle callback methods.