show documentation & source size on crate-detail page

[syphar]

The sizes we started collecting in #2644

on this page: https://docs.rs/crate/itertools/latest

I could imagine showing just the doc & source size for the latest build, perhaps similar to coverage?

[GuillaumeGomez]

I think it makes more sense to only show it for the last version.

[syphar]

you mean the latest build?

the crate-detail page is version specific, so we would show the size of that version, if available

[GuillaumeGomez]

Ah right, forgot about that. Then sure. Sending a PR.