doc: fix Block interface parameters order

The Effective Go document references the crypto/cipher Block
interface, but the parameters' names are swapped. This change
alignes them to the crypto definition, to avoid confusion.

Fixes #33432

Change-Id: I8b9aac4dc6af3eec968bbc8f3ee5366b99016fcc
Reviewed-on: https://go-review.googlesource.com/c/go/+/188797Reviewed-by: Ian Lance Taylor <iant@golang.org>

doc/effective_go.html

@@ -2282,8 +2282,8 @@ The  <code>crypto/cipher</code> interfaces look like this:
 <pre>
 type Block interface {
     BlockSize() int
-    Encrypt(src, dst []byte)
-    Decrypt(src, dst []byte)
+    Encrypt(dst, src []byte)
+    Decrypt(dst, src []byte)
 }
 
 type Stream interface {