doc/go1.4.txt: reflect.Type.Comparable

CC=golang-codereviews
https://golang.org/cl/138530044

doc/go1.4.txt

@@ -23,6 +23,7 @@ net/http: add Request.BasicAuth method (CL 76540043)
 net/http: add Transport.DialTLS hook (CL 137940043)
 net/http/httputil: add ReverseProxy.ErrorLog (CL 132750043)
 os: implement symlink support for windows (CL 86160044)
+reflect: add type.Comparable (CL 144020043)
 runtime: implement monotonic clocks on windows (CL 108700045)
 runtime/race: freebsd is supported (CL 107270043)
 syscall: Setuid, Setgid are disabled on linux platforms. On linux those syscalls operate on the calling thread, not the whole process. This does not match the semantics of other platforms, nor the expectations of the caller, so the operations have been disabled until issue 1435 is resolved (CL 106170043)