Add page descriptions to docs (#2075)

Co-authored-by: mfwmyfacewhen <94880365+mfwmyfacewhen@users.noreply.github.com>
Signed-off-by: Jonah Aragon <github@aragon.science>
Signed-off-by: Daniel Gray <dngray@privacyguides.org>

docs/advanced/communication-network-types.md

@@ -1,6 +1,7 @@
 ---
 title: "Types of Communication Networks"
 icon: 'material/transit-connection-variant'
+description: An overview of several network architectures commonly used by instant messaging applications.
 ---
 
 There are several network architectures commonly used to relay messages between people. These networks can provide different privacy guarantees, which is why it's worth considering your [threat model](../basics/threat-modeling.md) when deciding which app to use.

docs/advanced/dns-overview.md

@@ -1,6 +1,7 @@
 ---
 title: "DNS Overview"
 icon: material/dns
+description: The Domain Name System is the "phonebook of the internet," helping your browser find the website it's looking for.
 ---
 
 The [Domain Name System](https://en.wikipedia.org/wiki/Domain_Name_System) is the 'phonebook of the Internet'. DNS translates domain names to IP addresses so browsers and other services can load Internet resources, through a decentralized network of servers.

docs/advanced/tor-overview.md

@@ -1,6 +1,7 @@
 ---
 title: "Tor Overview"
 icon: 'simple/torproject'
+description: Tor is a free to use, decentralized network designed for using the internet with as much privacy as possible.
 ---
 
 Tor is a free to use, decentralized network designed for using the internet with as much privacy as possible. If used properly, the network enables private and anonymous browsing and communications.