samples: net: vlan: improve README formatting

simple tweaks to improve HTML rendering of the
vLAN README

Signed-off-by: Benjamin Cabé <[email protected]>

Author: kartben

samples/net/vlan/README.rst

@@ -22,8 +22,8 @@ Building and Running
 ********************
 
 A good way to run this VLAN application is with QEMU as described in
-:ref:`networking_with_eth_qemu`. You can use *zeth-vlan.conf* configuration
-file when running *net-setup.sh* script in Linux like this:
+:ref:`networking_with_eth_qemu`. You can use :file:`zeth-vlan.conf` configuration
+file when running :file:`net-setup.sh` script in Linux like this:
 
 .. code-block:: console
 
@@ -41,8 +41,8 @@ Follow these steps to build the VLAN sample application:
    :goals: build
    :compact:
 
-The default configuration file prj.conf creates two virtual LAN networks
-with these settings:
+The default configuration file :zephyr_file:`samples/net/vlan/prj.conf` creates
+two virtual LAN networks with these settings:
 
 - VLAN tag 100: IPv4 198.51.100.1 and IPv6 2001:db8:100::1
 - VLAN tag 200: IPv4 203.0.113.1 and IPv6 2001:db8:200::1
@@ -51,8 +51,8 @@ Setting up Linux Host
 =====================
 
 The :zephyr_file:`samples/net/vlan/vlan-setup-linux.sh` provides a script that
-can be executed on the Linux host. It creates two VLAN interfaces *vlan.100*
-and *vlan.200* on the Linux host and creates routes to Zephyr.
+can be executed on the Linux host. It creates two VLAN interfaces ``vlan.100``
+and ``vlan.200`` on the Linux host and creates routes to Zephyr.
 
 If everything is configured correctly, you will be able to successfully execute
 the following commands on the Linux host.
@@ -64,6 +64,6 @@ the following commands on the Linux host.
     ping -c 1 2001:db8:200::1
     ping -c 1 203.0.113.1
 
-The network packets to *2001:db8:100::1* or *198.51.100.1* will have VLAN
+The network packets to ``2001:db8:100::1`` or ``198.51.100.1`` will have VLAN
 tag 100 set to them. The vlan tag 200 will be set to network packets to
-*2001:db8:200::1* or *203.0.113.1*.
+``2001:db8:200::1`` or ``203.0.113.1``.