Fix the docs warning detected by the vale Acronym rule

doc/administration/nfs.md

@@ -351,7 +351,7 @@ Any `Operation not permitted` errors means you should investigate your NFS serve
 If the traffic between your NFS server and NFS client(s) is subject to port filtering
 by a firewall, then you need to reconfigure that firewall to allow NFS communication.
 
-[This guide from TDLP](https://tldp.org/HOWTO/NFS-HOWTO/security.html#FIREWALLS)
+[This guide from The Linux Documentation Project (TDLP)](https://tldp.org/HOWTO/NFS-HOWTO/security.html#FIREWALLS)
 covers the basics of using NFS in a firewalled environment. Additionally, we encourage you to
 search for and review the specific documentation for your operating system or distribution and your firewall software.