Indexers names clarification

## Environment Details
* EclipseStore Version: 3.1.0
* JDK version: 25
* OS: MacOS

## Describe the bug
I think the GigaMap  documentation in the section for naming  indexes should mention that indexer names within the same GigaMap must be unique, otherwise they are overridden (got bitten by this issue!). This is  important especially when the name are auto-generated.
