Fix type-checking errors in snippets (code only, no .md)

This commit both:
- Fixes pre-existing mistakes in snippets, aka wrong code samples.
- Adds hidden (`@hide`) statements that do not appear in the docs,
  but satisfy typecheckers.

qdrant-landing/content/documentation/headless/snippets/update-vectors/simple/go.go

@@ -12,6 +12,8 @@ func Main() {
 		Port: 6334,
 	})
 
+	if err != nil { panic(err) } // @hide
+
 	client.UpdateVectors(context.Background(), &qdrant.UpdatePointVectors{
 		CollectionName: "{collection_name}",
 		Points: []*qdrant.PointVectors{

qdrant-landing/content/documentation/headless/snippets/update-vectors/simple/java.java

@@ -4,11 +4,17 @@ import static io.qdrant.client.PointIdFactory.id;
 import static io.qdrant.client.VectorFactory.vector;
 import static io.qdrant.client.VectorsFactory.namedVectors;
 
+import io.qdrant.client.grpc.Points.PointVectors;
 import java.util.List;
 import java.util.Map;
 
 public class Snippet {
         public static void run() throws Exception {
+                // @hide-start
+                io.qdrant.client.QdrantClient client =
+                    new io.qdrant.client.QdrantClient(io.qdrant.client.QdrantGrpcClient.newBuilder("localhost", 6334, false).build());
+                // @hide-end
+
                 client
                     .updateVectorsAsync(
                         "{collection_name}",

qdrant-landing/content/documentation/headless/snippets/update-vectors/simple/rust.rs

@@ -5,6 +5,8 @@ use qdrant_client::qdrant::{
 };
 
 pub async fn main() -> anyhow::Result<()> {
+    let client = qdrant_client::Qdrant::from_url("http://localhost:6334").build()?; // @hide
+
     client
         .update_vectors(
             UpdatePointVectorsBuilder::new(