fix prettier errors

apps/www/_blog/2023-07-13-pgvector-performance.mdx

@@ -309,6 +309,7 @@ pgvector is still early in development. As with any open source tool, it needs t
 What's next on the roadmap? Andrew has an impressive list of features [planned for v0.5.0](https://github.com/pgvector/pgvector/issues/27):
 
 ✅ [Adding HNSW](https://supabase.com/blog/increase-performance-pgvector-hnsw): an index with better speed & accuracy than IVFFlat (at a higher memory cost)
+
 - Product quantization: better storage for IVFFLAT, improving speed and recall
 - Parallel index builds: building your IVFFLAT indexes will be much faster