removeVertex does not update graph size

[thaumavorio]

The current implementations of removeVertex use the stored size without any updates. One would expect the number of edges to decrease by the degree of the vertex (at least for simple graphs).

For example (a bit verbose for demonstration purposes):
size . removeVertex 1 . insertEdgePair (1,1) $ insertVertex 1 (empty :: UGraph Int ()) is 1 even though the edge list is empty.