Added .NET client API guide for the Search API. #1044

Job	Run time
Integration OpenSearch (2.9.0)	10m 1s
Integration OpenSearch Unreleased (1.x)	7m 47s
Integration OpenSearch (2.8.0)	8m 5s
Integration OpenSearch Unreleased (2.x)	15m 14s
Integration OpenSearch (2.7.0)	7m 41s
Integration OpenSearch Unreleased (main)	8m 36s
Integration OpenSearch (2.6.0)	8m 27s
Integration OpenSearch (2.5.0)	8m 4s
Integration OpenSearch (2.4.1)	8m 9s
Integration OpenSearch (2.3.0)	7m 39s
Integration OpenSearch (2.2.1)	6m 56s
Integration OpenSearch (2.1.0)	7m 38s
Integration OpenSearch (2.0.1)	7m 48s
Integration OpenSearch (1.3.11)	8m 20s
Integration OpenSearch (1.2.4)	8m 5s
Integration OpenSearch (1.1.0)	7m 10s
	2h 15m 40s

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