encoding/base64: fix typo in decodeQuantum docs

Change-Id: I643540bcea574d8a70b79237d97097dcc7368766
GitHub-Last-Rev: e2be58d1ab84f91dfbba1067aae7145f24fd650d
GitHub-Pull-Request: golang/go#28125
Reviewed-on: https://go-review.googlesource.com/c/141119Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/encoding/base64/base64.go

@@ -270,7 +270,7 @@ func (e CorruptInputError) Error() string {
 	return "illegal base64 data at input byte " + strconv.FormatInt(int64(e), 10)
 }
 
-// decodeQuantum decodes up to 4 base64 bytes. It takes for parameters
+// decodeQuantum decodes up to 4 base64 bytes. The received parameters are
 // the destination buffer dst, the source buffer src and an index in the
 // source buffer si.
 // It returns the number of bytes read from src, the number of bytes written