Don't Make str field private
Making fields in std and extra : private  #4386
Removed Unnecessary comments and white spaces  #4386
Removed unnecessary comments and white spaces as suggested
Removed the unnecesary comments
Removed the file src/libstd/unstable/extfmt.r
Making ai_next field public
auto merge of #9969 : reedlepee123/rust/priv_fields, r=bstrie