core: Hide GC docs
Update 0.6 release notes
Add missing authors
core: As per #4898, finish impls for one-tuples
auto merge of #5547 : catamorphism/rust/issue-4898, r=catamorphism
auto merge of #5560 : brson/rust/relnotes, r=brson

r?
option: rm functions that duplicate methods
auto merge of #5414 : thestinger/rust/option, r=catamorphism