go spec: clarify return type of append, argument type for ...T parameters
go spec: clarify return type of append, argument type for ...T parameters

R=iant, ken2, r, rsc
CC=golang-dev
http://codereview.appspot.com/2774041

mhennings/marcohennings-go,glycerine/jeaten-go-arrayof-structof,bryanxu/go-zh,mhennings/marcohennings-go,sanjosh/sanjos100-tipc,webfd/go-zh,npe9/noahevans-go9,d0f/go-zh,rflanagan/reginaldflanagan-project1,scirelli/scirelli-go,rdp/rogerpack2005-golang,bryanxu/go-zh,rdp/rogerpack2005-golang,mhennings/marcohennings-go,glycerine/jeaten-go-arrayof-structof,Triskite/willstone-goclone,d0f/go-zh,bryanxu/go-zh,rdp/rogerpack2005-golang,Triskite/willstone-goclone,npe9/noahevans-go9,sanjosh/sanjos100-tipc,glycerine/jeaten-go-arrayof-structof,sanjosh/sanjos100-tipc,glycerine/jeaten-go-arrayof-structof,mhennings/marcohennings-go,rdp/rogerpack2005-golang,scirelli/scirelli-go,Triskite/willstone-goclone,rflanagan/reginaldflanagan-project1,glycerine/jeaten-go-arrayof-structof,scirelli/scirelli-go,rflanagan/reginaldflanagan-project1,scirelli/scirelli-go,Triskite/willstone-goclone,webfd/go-zh,sanjosh/sanjos100-tipc,d0f/go-zh,d0f/go-zh,mhennings/marcohennings-go,scirelli/scirelli-go,mhennings/marcohennings-go,webfd/go-zh,rdp/rogerpack2005-golang,npe9/noahevans-go9,sanjosh/sanjos100-tipc,scirelli/scirelli-go,rflanagan/reginaldflanagan-project1,npe9/noahevans-go9,d0f/go-zh,d0f/go-zh,bryanxu/go-zh,webfd/go-zh,npe9/noahevans-go9,rdp/rogerpack2005-golang,bryanxu/go-zh,bryanxu/go-zh,mhennings/marcohennings-go,webfd/go-zh,scirelli/scirelli-go,Triskite/willstone-goclone,glycerine/jeaten-go-arrayof-structof,npe9/noahevans-go9,npe9/noahevans-go9,Triskite/willstone-goclone,sanjosh/sanjos100-tipc,webfd/go-zh,sanjosh/sanjos100-tipc,glycerine/jeaten-go-arrayof-structof,Triskite/willstone-goclone,d0f/go-zh,scirelli/scirelli-go,mhennings/marcohennings-go,d0f/go-zh,webfd/go-zh,rflanagan/reginaldflanagan-project1,npe9/noahevans-go9,bryanxu/go-zh,rdp/rogerpack2005-golang,bryanxu/go-zh,rdp/rogerpack2005-golang,sanjosh/sanjos100-tipc,webfd/go-zh,rflanagan/reginaldflanagan-project1,glycerine/jeaten-go-arrayof-structof,rflanagan/reginaldflanagan-project1,Triskite/willstone-goclone,rflanagan/reginaldflanagan-project1