encoding/gob: fix a typo in the package documentation

Change-Id: I6aee75a6ae1470dfc658d72a5b6508fb93503057
Reviewed-on: https://go-review.googlesource.com/69115Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>

src/encoding/gob/doc.go

@@ -381,7 +381,7 @@ Now we can send the Point value. Again the field number resets to -1:
 	07	// this value is 7 bytes long
 	ff 82	// the type number, 65 (1 byte (-FF) followed by 65<<1)
 	01	// add one to field number, yielding field 0
-	2c	// encoding of signed "22" (0x22 = 44 = 22<<1); Point.x = 22
+	2c	// encoding of signed "22" (0x2c = 44 = 22<<1); Point.x = 22
 	01	// add one to field number, yielding field 1
 	42	// encoding of signed "33" (0x42 = 66 = 33<<1); Point.y = 33
 	00	// end of structure