[Doc] Clarify full-compaction changelog integrality

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/paimon/issues) and found nothing similar.

### Motivation

Currently, the [doc](https://paimon.apache.org/docs/master/primary-key-table/changelog-producer/#full-compaction) of full compaction changelog producer states that "Full compaction changelog producer can produce complete changelog for any type of source", however, when `full-compaction.delta-commits` is greater than 1, the intermediate changes across multiple snapshots will be ignored.

Iceberg CDC refers to this as [net changes](https://iceberg.apache.org/docs/latest/spark-procedures/#change-data-capture), and Snowflake refers to this as Minimum-delta changes, both differ from a "complete" changelog. So I think this also worth clarifying in the Paimon doc, because we usually consider net changes and complete changes to be different.

### Solution

I think we should clarify that the full compaction changelog producer will only output complete changes when `full-compaction.delta-commits` is set to 1; when `full-compaction.delta-commits` is set to a value greater than 1, intermediate changes across the serveral delta snapshots will be ignored.

cc @JingsongLi What do you think?

### Anything else?

_No response_

### Are you willing to submit a PR?

- [x] I'm willing to submit a PR!

Start with the linked Paimon documentation section for the full compaction changelog producer and read the explanation of full-compaction.delta-commits. Clarify that complete changes apply when the value is 1, while values greater than 1 ignore intermediate changes across snapshots; done when the distinction from net changes is unambiguous.

Written by the indexing model from the issue text.