docs: round out v5-prep doc fixes

- guides/routing.md: add COORDINATOR and NULL rows to the policy
  override env-var table so it matches the 10 policy types in
  policy_override_env.go (USER_GUIDE.md already says "10 variables").
- guides/search.md: replace three Transport: &opensearchtransport.Client{Router: ...}
  blocks with Router: ... directly on opensearch.Config. The old form
  did not compile -- opensearch.Config.Transport is http.RoundTripper
  and *opensearchtransport.Client does not implement it; the canonical
  field for the router has been Config.Router since the routing system
  was introduced.

Signed-off-by: Sean Chittenden <sean.chittenden@crowdstrike.com>

Author: sean-

guides/routing.md

@@ -2038,6 +2038,8 @@ Each policy type has a corresponding environment variable:
 | `OPENSEARCH_GO_POLICY_ROUTER`          | poolRouter       |
 | `OPENSEARCH_GO_POLICY_ROLE`            | RolePolicy       |
 | `OPENSEARCH_GO_POLICY_ROUNDROBIN`      | RoundRobinPolicy |
+| `OPENSEARCH_GO_POLICY_COORDINATOR`     | CoordinatorPolicy |
+| `OPENSEARCH_GO_POLICY_NULL`            | NullPolicy       |
 | `OPENSEARCH_GO_POLICY_INDEX_ROUTER`    | IndexRouter      |
 | `OPENSEARCH_GO_POLICY_DOCUMENT_ROUTER` | DocRouter        |
 

guides/search.md

@@ -64,9 +64,7 @@ For search-heavy applications, you can configure the client to automatically rou
 		DiscoverNodesInterval: 5 * time.Minute,
 
 		// Configure automatic routing to data nodes for search operations
-		Transport: &opensearchtransport.Client{
-			Router: router,
-		},
+		Router: router,
 	})
 	if err != nil {
 		return err
@@ -311,15 +309,13 @@ For production search workloads, you can optimize performance by ensuring search
 		DiscoverNodesInterval: 5 * time.Minute,
 
 		// Use data-preferred router for search optimization
-		Transport: &opensearchtransport.Client{
-			Router: opensearchtransport.NewRouter(
-				func() opensearchtransport.Policy {
-					policy, _ := opensearchtransport.NewRolePolicy(opensearchtransport.RoleData)
-					return policy
-				}(),
-				opensearchtransport.NewRoundRobinPolicy(),
-			),
-		},
+		Router: opensearchtransport.NewRouter(
+			func() opensearchtransport.Policy {
+				policy, _ := opensearchtransport.NewRolePolicy(opensearchtransport.RoleData)
+				return policy
+			}(),
+			opensearchtransport.NewRoundRobinPolicy(),
+		),
 	})
 	if err != nil {
 		return err
@@ -360,9 +356,7 @@ The router automatically detects operation types and routes them to the most app
 		DiscoverNodesOnStart:  &discoverOnStart,
 		DiscoverNodesInterval: 5 * time.Minute,
 
-		Transport: &opensearchtransport.Client{
-			Router: router,
-		},
+		Router: router,
 	})
 	if err != nil {
 		return err