docs: add nested loop example (#6948)

Author: anna-geller

core/src/main/java/io/kestra/plugin/core/flow/ForEach.java

@@ -139,6 +139,61 @@
                             - sleep {{ parent.taskrun.value }}
                 """
         ),
+        @Example(
+            full = true,
+            title = """
+                This example demonstrates processing data across nested loops of S3 buckets, years, and months. \
+                It generates structured identifiers (e.g., `bucket1_2025_March`) by combining values from each loop level, \
+                while accessing parent loop values like years and buckets, which can be useful for partitioned \
+                storage paths or time-based datasets. The flow uses dynamic expressions referencing parent context.""",
+            code = """
+                id: loop_multiple_times
+                namespace: company.team
+
+                inputs:
+                  - id: s3_buckets
+                    type: ARRAY
+                    itemType: STRING
+                    defaults:
+                      - bucket1
+                      - bucket2
+
+                  - id: years
+                    type: ARRAY
+                    itemType: INT
+                    defaults:
+                      - 2025
+                      - 2026
+
+                  - id: months
+                    type: ARRAY
+                    itemType: STRING
+                    defaults:
+                      - March
+                      - April
+
+                tasks:
+                  - id: buckets
+                    type: io.kestra.plugin.core.flow.ForEach
+                    values: "{{inputs.s3_buckets}}"
+                    tasks:
+                      - id: year
+                        type: io.kestra.plugin.core.flow.ForEach
+                        values: "{{inputs.years}}"
+                        tasks:
+                          - id: month
+                            type: io.kestra.plugin.core.flow.ForEach
+                            values: "{{inputs.months}}"
+                            tasks:
+                              - id: full_table_name
+                                type: io.kestra.plugin.core.log.Log
+                                message: |
+                                  Full table name: {{parents[1].taskrun.value }}_{{parent.taskrun.value}}_{{taskrun.value}}
+                                  Direct/current loop (months): {{taskrun.value}}
+                                  Value of loop one higher up (years): {{parents[0].taskrun.value}} 
+                                  Further up (table types): {{parents[1].taskrun.value}}
+                """
+        ),        
     }
 )
 public class ForEach extends Sequential implements FlowableTask<VoidOutput> {