Present in tip:

Maps are sent as an unsigned count followed by that many key, element pairs. Empty but
non-nil maps are sent, so if the sender has allocated a map, the receiver will allocate
a map even no elements are transmitted.

Suggested change:
diff -r 86c06191bea6 src/pkg/encoding/gob/doc.go
--- a/src/pkg/encoding/gob/doc.go   Wed Sep 19 07:04:12 2012 +0900
+++ b/src/pkg/encoding/gob/doc.go   Wed Sep 19 09:20:47 2012 +0930
@@ -118,7 +118,7 @@
 
 Maps are sent as an unsigned count followed by that many key, element
 pairs. Empty but non-nil maps are sent, so if the sender has allocated
-a map, the receiver will allocate a map even no elements are
+a map, the receiver will allocate a map even if no elements are
 transmitted.
 
 Structs are sent as a sequence of (field number, field value) pairs.  The field

NB: Note that zero is singular. (May vary by locale).