Write our own summaries of std types' API surface

Currently our section on std library types consists of a slide for each type with an example, and when teaching this is nice as an intro but gets followed up by a dive into the API docs at https://std.rs/ to cover more comprehensively all the API surface that students should know.

We focus on:
- shared API method and patterns that are not captured by traits
- novel APIs around ownership and borrowing (like `into_boxed_slice`, `leak`, and `split_at_mut`)
- interesting string APIs around the `Pattern` trait and UTF-8
- slice APIs for sorting and partitioning
- methods inherited via `Deref` impls
- the `HashMap` `Entry` API

But there's a lot that we have to scroll past and ignore because it's boring, rarely useful, unstable, etc..

It would be nice to have our own summaries of these APIs that present things with emphasis on what we care about and skip the stuff that doesn't matter for teaching.

I don't think these will likely fit into small slides, so maybe someone with opinions on slide heights/scrolling should opine here.