Update documentation to use `from()` to initialize `HashMap`s and `BTreeMap`s#91482

Merged

bors merged 3 commits intorust-lang:masterfrom JosephTLyons:update-HashMap-and-BTreeMap-documentation

Dec 11, 2021

+75-57

Commits on Dec 2, 2021

Use HashMap::from() instead of using HashMap::new() with HashMap::insert()
JosephTLyons
committed
Use BTreeMap::from() instead of using BTreeMap::new() with BTreeMap::insert()
JosephTLyons
committed

Commits on Dec 3, 2021

Make HashMaps mutable again
JosephTLyons
committed