Feature request: Reverse index of packages that depend on this package

[carols10cents]

I love looking at examples of how to use a library, and libraries that use the library I'm interested in are a great source of those examples.

To that end, it'd be awesome if crates.io, since it has this information, could show on the page somewhere the list of libraries that depend on the one I'm currently looking at.

So for example, the gcc crate would show that the time crate has the gcc crate as a dependency. If I wanted to see a real world example of the gcc crate, I could go look at what the time crate is doing with it.

Thanks!!! 🌴