Regenerate snippet .md files

Run `./generate-md.py` to update generated markdown files after
semi-manual changes made in the previous commit.
This commit serves as a gist of fixed issues found in snippets.

(it's easier to review 250 lines diff rather than 31k lines diff, isn't it?)

qdrant-landing/content/documentation/headless/snippets/query-groups/basic/generated/java.md

@@ -1,4 +1,7 @@
 ```java
+import static io.qdrant.client.QueryFactory.nearest;
+
+import io.qdrant.client.grpc.Points.QueryPointGroups;
 import io.qdrant.client.grpc.Points.SearchPointGroups;
 import java.util.List;