books: add debian release to remaining books

[der.hans]

moin moin,

attached is a diff to add debian release for the remaining books.

Debian-Paketmanagement is actually already set for Buster, so we can list
that rather than Stretch if that's preferred.

That book, and others, covers multiple releases of debian and Ubuntu. I
would like to work with authors to cover that aspect in the descriptions.

ciao,

der.hans
--
#  https://www.LuftHans.com   https://www.PhxLinux.org
#  Stell dir vor, es ist Krieg und keiner geht hin...
diff --git a/english/doc/books.data b/english/doc/books.data
index 5bb84a89bf1..0f709f5816b 100644
--- a/english/doc/books.data
+++ b/english/doc/books.data
@@ -49,7 +49,6 @@
 <bookentry>
   <title The Debian Administrator's Handbook, Debian Jessie from Discovery to Mastery>
   <author Rapha&euml;l Hertzog, Roland Mas>
-  <debian-release "8/Jessie">
   <publisher Freexian>
   <URL "https://debian-handbook.info";>
   <available
@@ -74,7 +73,6 @@
 <bookentry>
   <title Debian GNU/Linux Desktop Survival Guide>
   <author Graham J Williams>
-  <debian-release "9/Stretch">
   <publisher Togaware>
   <URL "http://www.togaware.com/linux/survivor/";>
   <email graham.willi...@togaware.com>
@@ -92,7 +90,6 @@
 <bookentry>
   <title Debian 8 Jessie : GNU/Linux>
   <author Rapha&euml;l Hertzog, Roland Mas>
-  <debian-release "8/Jessie">
   <publisher Eyrolles>
   <URL "https://raphaelhertzog.fr/livre/cahier-admin-debian/";>
   <available
@@ -116,7 +113,6 @@
 <bookentry>
   <title Debian-Paketmanagement>
   <author Axel Beckert, Frank Hofmann>
-  <debian-release "9/Stretch">
   <publisher Onyx Neon>
   <URL "http://www.dpmb.org/";>
   <email b...@dpmb.org>
@@ -133,7 +129,6 @@
 <bookentry>
   <title Debian GNU/Linux: Das umfassende Handbuch (aktuell zu »Jessie«)>
   <author Heike Jurzik>
-  <debian-release "8/Jessie">
   <publisher Rheinwerk Computing>
   <URL "https://www.rheinwerk-verlag.de/debian-gnulinux_3847/";>
   <available
@@ -149,7 +144,6 @@
 <bookentry>
   <title Debian GNU/Linux Anwenderhandbuch>
   <author Frank Ronneburg>
-  <debian-release "7/Wheezy">
   <publisher Addison Wesley>
   <URL "http://debiananwenderhandbuch.de/";>
   <email f...@debiananwenderhandbuch.de>
@@ -160,7 +154,6 @@
 <bookentry>
   <title Debian 管理者ハンドブック、Debian Jessie との出会いから習熟まで>
   <author Rapha&euml;l Hertzog, Roland Mas>
-  <debian-release "8/Jessie">
   <publisher Freexian>
   <URL "https://debian-handbook.info/";>
   <available
@@ -186,7 +179,6 @@
 <bookentry>
   <title 데비안 리눅스 활용과 보안 [칼리 리눅스의 원조]>
   <author TaeHee Lee (Annihilator), Dong-jin Oh (Firstbood)>
-  <debian-release "8/Jessie">
   <publisher AcornPub>
   <URL "http://acornpub.co.kr/book/debian-kali";>
   <available
@@ -214,7 +206,6 @@
 <bookentry>
   <title El manual del Administrador de Debian>
   <author Rapha&euml;l Hertzog, Roland Mas>
-  <debian-release "8/Jessie">
   <publisher Freexian>
   <URL "https://debian-handbook.info/";>
   <available