change codenames to jessie as stable POV in docs

doc/apt-verbatim.ent

@@ -228,10 +228,10 @@
 <!ENTITY apt-product-version "1.0.9.1">
 
 <!-- (Code)names for various things used all over the place -->
-<!ENTITY oldstable-codename "squeeze">
-<!ENTITY stable-codename "wheezy">
-<!ENTITY testing-codename "jessie">
-<!ENTITY stable-version "7">
+<!ENTITY oldstable-codename "wheezy">
+<!ENTITY stable-codename "jessie">
+<!ENTITY testing-codename "stretch">
+<!ENTITY stable-version "8">
 <!ENTITY ubuntu-codename "trusty">
 
 <!-- good and bad just refers to matching and not matching a pattern…