Remove collection-specific `with_capacity` documentation from `std::collections`
Fixes#59931
The style of `std::collections` module doc is very much a beginner friendly guide, and documenting niche, collection-specific behaviour feels out of place, if not brittle.
The note about `VecDeque` is outdated (see issue), and while `Vec` probably won't change its guarantees any time soon, the users who are interested in its allocation properties will find that in its own documentation.
Mazdak Farrokhzad
43985d965a