Add documentation on how to check-in to an environment with CheckInUtils (#11826)

Author: maxhov

platform-includes/crons/setup/java.mdx

@@ -54,6 +54,29 @@ CheckInUtils.withCheckIn("<monitor-slug>", monitorConfig) {
 }
 ```
 
+You can also check-in to a specific environment.
+
+```java
+import io.sentry.MonitorSchedule;
+import io.sentry.MonitorScheduleUnit;
+import io.sentry.util.CheckInUtils;
+
+String result = CheckInUtils.withCheckIn("<monitor-slug>", "<environment-name>", () -> {
+    // Execute your scheduled task here...
+    return "computed result";
+});
+```
+
+```kotlin
+import io.sentry.MonitorSchedule
+import io.sentry.MonitorScheduleUnit
+import io.sentry.util.CheckInUtils
+
+CheckInUtils.withCheckIn("<monitor-slug>", "<environment-name>") {
+    // Execute your scheduled task here...
+}
+```
+
 ### Manually sending check-ins
 
 It is also possible to manually send check-ins.