Print information about static nature of graph in display

[simsurace]

The show function is only overloaded for inline printing, but when displaying the graph, the information about its static nature is missing, potentially confusing users:

julia> g
{58089, 120148} directed simple Int32 graph

julia> (g, nothing)
({58089, 120148} directed simple static {Int32, Int32} graph, nothing)

This PR fixes that.

[KristofferC]

I wonder if the 2 arg show method should perhaps be removed?

[simsurace]

I'm never quite sure about this. Wouldn't it then print the "ugly" style when inline?