Update the Preludes chapter for the 2021 edition changes to the standard library prelude#1136

Merged

ehuss merged 2 commits intorust-lang:masterfrom

mattheww:2022-01_preludes

Jan 24, 2022

Commits on Jan 15, 2022

Update for 2021 edition standard library prelude changes
mattheww
committed

Commits on Jan 20, 2022

2021 edition standard library prelude changes: address review comments
mattheww
committed