Shim for sly-inspector

[jgarte]

Sly still needs a shim for the sly-inspector buffer:

For example, sly-inspector-pop is caught in normal mode by meow-right.

I'll try to work on this soonish unless someone takes it up first or someone thinks that there is a better approach to take here. I might just rebind sly-inspector-pop to something else, for example.