expand the documentation on the `Unpin` trait#53104

Merged

bors merged 7 commits intorust-lang:masterfrom

nivkner:unpin_doc

Aug 21, 2018

Commits on Aug 7, 2018

remove general pinning information from Unpin trait
nivkner
committed

Commits on Aug 16, 2018

add example for moving out of pointer
nivkner
committed

Commits on Aug 17, 2018

clarify use of Unpin and pinning types
nivkner
committed