[DOCS] Add search xref tip to `query_string` docs (#76728)

Adds a tip containing a cross-reference to the "Search your data" docs.
This is the preferred starting point for ES search.

docs/reference/query-dsl/query-string-query.asciidoc

@@ -4,6 +4,9 @@
 <titleabbrev>Query string</titleabbrev>
 ++++
 
+TIP: This page contains information about the `query_string` query type. For
+information about running a search query in {es}, see <<search-your-data>>.
+
 Returns documents based on a provided query string, using a parser with a strict
 syntax.