rephrasing in terms of Lucene docs

Author: ishansrivastava90

articles/search/search-limits-quotas-capacity.md

@@ -62,7 +62,7 @@ To determine whether your service has document limits, check the Usage tile in t
 
   ![Usage tile](media/search-limits-quotas-capacity/portal-usage-tile.png)
 
-<sup>1</sup> Even though there aren't any SKU specific document limits, every index is still subject to a maximum safe limit to ensure stability of the service. The number of documents is bound by an underlying lucene limit. It's hard to precisely determine the limit as it depends on factors like number of complex collections and number of internal sub-indexes modeling the original index. For indexes without any complex collections, it is roughly around 25 billion. Using complex collections can significantly lower this limit.
+<sup>1</sup> Even though there aren't any SKU specific document limits, every index is still subject to a maximum safe limit to ensure stability of the service. This limit comes from Lucene. Every Azure Search document is internally indexed as one or more Lucene documents. The number of Lucene documents per Azure search document depends on the total number of elements in complex collection fields. Each element is indexed as a separate Lucene document. For example, a document with 3 elements in a complex collection field, will be indexed as 4 Lucene documents - 1 for the document itself and 3 for the elements. The maximum number of Lucene documents that can be indexed is roughly 25 billion which is the upper bound for the number of documents in an Azure search index.
 
 ### Regions previously having document limits