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/delete-payload/by-filter/go.go

@@ -12,6 +12,8 @@ func Main() {
 	    Port: 6334,
 	})
 
+	if err != nil { panic(err) } // @hide
+
 	client.DeletePayload(context.Background(), &qdrant.DeletePayloadPoints{
 	    CollectionName: "{collection_name}",
 	    Keys:           []string{"color", "price"},

qdrant-landing/content/documentation/headless/snippets/delete-payload/by-filter/java.java

@@ -2,10 +2,16 @@ package com.example.snippets_amalgamation;
 
 import static io.qdrant.client.ConditionFactory.matchKeyword;
 
+import io.qdrant.client.grpc.Common.Filter;
 import java.util.List;
 
 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
                     .deletePayloadAsync(
                         "{collection_name}",

qdrant-landing/content/documentation/headless/snippets/delete-payload/by-filter/rust.rs

@@ -1,6 +1,8 @@
 use qdrant_client::qdrant::{Condition, DeletePayloadPointsBuilder, Filter};
 
 pub async fn main() -> anyhow::Result<()> {
+    let client = qdrant_client::Qdrant::from_url("http://localhost:6334").build()?; // @hide
+
     client
         .delete_payload(
             DeletePayloadPointsBuilder::new(

qdrant-landing/content/documentation/headless/snippets/delete-payload/by-point-id/go.go

@@ -12,6 +12,8 @@ func Main() {
 	    Port: 6334,
 	})
 
+	if err != nil { panic(err) } // @hide
+
 	client.DeletePayload(context.Background(), &qdrant.DeletePayloadPoints{
 	    CollectionName: "{collection_name}",
 	    Keys:           []string{"color", "price"},

qdrant-landing/content/documentation/headless/snippets/delete-payload/by-point-id/java.java

@@ -6,6 +6,11 @@ import java.util.List;
 
 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
                     .deletePayloadAsync(
                         "{collection_name}",

qdrant-landing/content/documentation/headless/snippets/delete-payload/by-point-id/rust.rs

@@ -1,6 +1,8 @@
 use qdrant_client::qdrant::{DeletePayloadPointsBuilder, PointsIdsList};
 
 pub async fn main() -> anyhow::Result<()> {
+    let client = qdrant_client::Qdrant::from_url("http://localhost:6334").build()?; // @hide
+
     client
         .delete_payload(
             DeletePayloadPointsBuilder::new(