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/query-points/by-existing-id-with-lookup/go.go

@@ -12,6 +12,8 @@ func Main() {
 		Port: 6334,
 	})
 
+	if err != nil { panic(err) } // @hide
+
 	client.Query(context.Background(), &qdrant.QueryPoints{
 		CollectionName: "{collection_name}",
 		Query:          qdrant.NewQueryID(qdrant.NewID("43cf51e2-8777-4f52-bc74-c2cbde0c8b04")),

qdrant-landing/content/documentation/headless/snippets/query-points/by-existing-id-with-lookup/rust.rs

@@ -1,5 +1,5 @@
 use qdrant_client::Qdrant;
-use qdrant_client::qdrant::{LookupLocationBuilder, PointId, Query, QueryPointsBuilder};
+use qdrant_client::qdrant::{LookupLocationBuilder, Query, QueryPointsBuilder};
 
 pub async fn main() -> anyhow::Result<()> {
     let client = Qdrant::from_url("http://localhost:6334").build()?;