docs: sync Haystack API reference on Docusaurus (#11640)

Co-authored-by: julian-risch <4181769+julian-risch@users.noreply.github.com>

Author: HaystackBot

docs-website/reference/haystack-api/websearch_api.md

@@ -20,7 +20,7 @@ Usage example:
 from haystack.components.websearch import SearchApiWebSearch
 from haystack.utils import Secret
 
-websearch = SearchApiWebSearch(top_k=10, api_key=Secret.from_env_var("SERPERDEV_API_KEY"))
+websearch = SearchApiWebSearch(top_k=10, api_key=Secret.from_env_var("SEARCHAPI_API_KEY"))
 results = websearch.run(query="Who is the boyfriend of Olivia Wilde?")
 
 assert results["documents"]