Test task docs suggest eager task configuration

### Issue type

Wrong or misleading information

### Problem description

Test task docs suggest eager task configuration

```
plugins {
id("java-library") // adds 'test' task
}

test {
// discover and execute JUnit4-based tests
useJUnit()
}
```

this makes configuration of the test task eager.

### Context (optional)

_No response_

### Page with the problem

https://docs.gradle.org/nightly/javadoc/org/gradle/api/tasks/testing/Test.html