Update LanNetworksHelp description for clarity

previously, it indicated that 
"If left blank, only the server's subnet is considered to be on the local network."
I tested this and afaik it's wrong, leaving it blank sets all RFC1918 addresses to local.

Author: linkandzelda91

src/strings/en-us.json

@@ -1034,7 +1034,7 @@
     "LabelYear": "Year",
     "LabelYoureDone": "You're Done!",
     "LabelZipCode": "Zip Code",
-    "LanNetworksHelp": "Comma separated list of IP addresses or IP/netmask entries for networks that will be considered on local network when enforcing bandwidth restrictions. If set, all other IP addresses will be considered to be on the external network and will be subject to the external bandwidth restrictions. If left blank, only the server's subnet is considered to be on the local network.",
+    "LanNetworksHelp": "Comma separated list of IP addresses or IP/netmask entries for networks that will be considered on local network when enforcing bandwidth and remote access restrictions.If left blank, all RFC1918 addresses are considered local.",
     "Large": "Large",
     "Larger": "Larger",
     "LastActive": "Last active",