Improvements to `BTreeSet` documentation.#38208

Merged

bors merged 4 commits intorust-lang:masterfrom frewsxcv:btreesetdocs

Dec 21, 2016

+58-11

Commits on Dec 14, 2016

Indicate BTreeSet in docs is code-like.
frewsxcv
committed

Commits on Dec 15, 2016

Commits on Dec 20, 2016

Indicate that BTreeSet::iter returns values in ascending order.
frewsxcv
committed