[skip ci] Add comment for CreateCollection (#11331)

Signed-off-by: Ndragondriver <jiquan.long@zilliz.com>

internal/proxy/impl.go

@@ -126,6 +126,7 @@ func (node *Proxy) ReleaseDQLMessageStream(ctx context.Context, request *proxypb
 	}, nil
 }
 
+// CreateCollection create a collection by the schema.
 func (node *Proxy) CreateCollection(ctx context.Context, request *milvuspb.CreateCollectionRequest) (*commonpb.Status, error) {
 	if !node.checkHealthy() {
 		return unhealthyStatus(), nil