Show more information about injectors in `wire show`

[zombiezen]

(Reporting on behalf of @vangent)

Is your feature request related to a problem? Please describe.

When examining provider sets referenced in an injector, you have to rely on code navigation in the editor to understand the full graph.

Describe the solution you'd like

For all injectors encountered in wire show, the command should print all the providers brought in with filename and line numbers.