Fix formatting: Remove double space in Linux Administration book entry (#12921)

Co-authored-by: harir03 <[email protected]>

Author: harir03

books/free-programming-books-langs.md

@@ -1503,7 +1503,7 @@ Books on general-purpose programming that don't focus on a specific language are
 * [Kali Linux: Professional Penetration-Testing Distribution](http://docs.kali.org)
 * [Learning Debian GNU/Linux](http://www.oreilly.com/openbook/debian/book/index.html)
 * [Linux 101 Hacks](http://thegeekstuff.s3.amazonaws.com/files/linux-101-hacks.zip) - Ramesh Natarajan (PDF)
-* [Linux Administration II : Linux as a Network Client](https://www.tuxcademy.org/download/en/adm2/adm2-en-manual.pdf) - Anselm Lingnau,Tobias Elsner (PDF)  (CC BY-SA)
+* [Linux Administration II : Linux as a Network Client](https://www.tuxcademy.org/download/en/adm2/adm2-en-manual.pdf) - Anselm Lingnau,Tobias Elsner (PDF) (CC BY-SA)
 * [Linux Advanced Routing & Traffic Control HOWTO](http://lartc.org)
 * [Linux Appliance Design: A Hands-On Guide to Building Linux Appliances](http://librta.org/book.html) - Bob Smith, John Hardin, Graham Phillips, Bill Pierce (PDF, EPUB, MOBI)
 * [Linux commands Notes for Professionals](https://goalkicker.com/LinuxBook/) - Compiled from StackOverflow documentation (PDF)