[Java] MapWithOrdinal javadoc doesn't describe actual behaviour

MapWithOrdinal states that ordinals are recycled when keys are removed, it does not currently do this and grows unbounded

**Reporter**: [Ryan Murray](https://issues.apache.org/jira/browse/ARROW-8947) / @rymurr
#### PRs and other links:
- [GitHub Pull Request apache/arrow#7276](https://github.com/apache/arrow/pull/7276)

_{**Note**: *This issue was originally created as [ARROW-8947](https://issues.apache.org/jira/browse/ARROW-8947). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Comienza con el Javadoc de MapWithOrdinal y revisa el pull request enlazado apache/arrow#7276 para entender el cambio previsto en la documentación. Se considera terminado cuando el Javadoc describe con precisión si los ordinales se reutilizan al eliminar claves y ya no contradice la implementación.

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