docs(all): fix markdown syntax and snippets

docs/services/systemd/systemd-networkd.md

@@ -4,7 +4,7 @@
 - link file
     Link file links hardware interface and kernel while booting
 - netdev file
-    netdev file defines virtual interface \(port, bridge\)
+    netdev file defines virtual interface (port, bridge)
 - network file
     network file defines network option above interfaces
 
@@ -12,7 +12,7 @@
 
 - reload
   - networkctl reload
-  - networkctl reconfigure \[interface name\]
+  - networkctl reconfigure [interface name]
 
 ## references
 
@@ -24,10 +24,10 @@
 ## Plans
 
 - Hypervisor's linux bridges work as L2 switch
-  - br0 is completely L2 switch \(LinkLocalAddressing=no\)
+  - br0 is completely L2 switch (LinkLocalAddressing=no)
   - br1 has ip address for hypervisor itself, but basically works as L2 switch whitch can deal with VLAN tags; id=1,10
-- Firewall's port \(wan\) works as Gateway which can conduct NAT
-- Firewall's port \(clients\) works as trunk port which can deal with VLAN tags; id=1,10,20
+- Firewall's port (wan) works as Gateway which can conduct NAT
+- Firewall's port (clients) works as trunk port which can deal with VLAN tags; id=1,10,20
 - Firewall's port
   - client, id = 1
   - server, id = 10

docs/services/systemd/systemd-quadlet.md

@@ -4,7 +4,7 @@ Quadlet is for defining container configuration and lifecycle combining systemd
 
 ## Rootless container
 
-Containers should be isolated from host OS. However, docker runs with root permission on daemon \(dockerd\). This means when one docker container has vulnerability and it is taken over, all the host system authority is threatened. Rootless container, podman runs without root permission and daemon so that even if one of containers is taken over, prevent the damage in host's normal user authority.
+Containers should be isolated from host OS. However, docker runs with root permission on daemon (dockerd). This means when one docker container has vulnerability and it is taken over, all the host system authority is threatened. Rootless container, podman runs without root permission and daemon so that even if one of containers is taken over, prevent the damage in host's normal user authority.
 
 Rootless container maps UID/GID between host and its own following namespace. Host's user UID/GID is mapped with container's root, and host's subuid/subgid defined on `/etc/subuid`, `/etc/subgid` is mapped with container's user UID/GID by default.