Better search when dragging out from a sequence port in VisualScript

**Godot version:**
3.1.1

**Issue description:**
The new node search in VisualScript has plenty of nodes that use sequence ports that the search when dragging out of a sequence port lacks. At least the nodes with a sequence port should be visible there. I would even go as far as saying that the drag-out search should be identical to the node search, just that it automatically connects the sequence port if there is one. That's how it's done in UE4 at least, and I see it as a faster workflow as searching by ctrl+f all the time.

**Steps to reproduce:**
Make a new VisualScript and hit ctrl+f or do "Search Nodes".