hash: rewrite comment on Hash.Sum method

Fixes #2530.

R=golang-dev, agl
CC=golang-dev
https://golang.org/cl/5449101

diff --git a/src/pkg/hash/hash.go b/src/pkg/hash/hash.go
index 0d7765dc505b155f26c7835c5af9db75c2d0f24c..8598f4e1b83ec242a8823f45775b5a66570599b7 100644 (file)
--- a/src/pkg/hash/hash.go
+++ b/src/pkg/hash/hash.go
@@ -13,9 +13,9 @@ type Hash interface {
        // It never returns an error.
        io.Writer
 
-       // Sum appends the current hash in the same manner as append(), without
-       // changing the underlying hash state.
-       Sum(in []byte) []byte
+       // Sum appends the current hash to b and returns the resulting slice.
+       // It does not change the underlying hash state.
+       Sum(b []byte) []byte
 
        // Reset resets the hash to one with zero bytes written.
        Reset()