use listings for file contents

local-zfs.adoc

@@ -265,7 +265,9 @@ pool errors.
 To activate the daemon it is necessary to edit `/etc/zfs/zed.d/zed.rc` with your
 favourite editor, and uncomment the `ZED_EMAIL_ADDR` setting:
 
+--------
 ZED_EMAIL_ADDR="root"
+--------
 
 Please note {pve} forwards mails to `root` to the email address
 configured for the root user.
@@ -312,7 +314,9 @@ run into low memory situations. Additionally, you can lower the
 To make the swappiness persistent, open `/etc/sysctl.conf` with
 an editor of your choice and add the following line:
 
- vm.swappiness = 10
+--------
+vm.swappiness = 10
+--------
 
 .Linux kernel `swappiness` parameter values
 [width="100%",cols="<m,2d",options="header"]

pct.adoc

@@ -140,8 +140,10 @@ File Format
 Container configuration files use a simple colon separated key/value
 format. Each line has the following format:
 
- # this is a comment
- OPTION: value
+-----
+# this is a comment
+OPTION: value
+-----
 
 Blank lines in those files are ignored, and lines starting with a `#`
 character are treated as comments and are also ignored.

pve-firewall.adoc

@@ -475,10 +475,11 @@ set it for the `default` interface configuration and enabling it explicitly on
 the interfaces which need it. This is also the case for other settings such as
 `forwarding`, `accept_ra` or `autoconf`.
 
-Here's a possible setup:
-----
-# /etc/sysconf.d/90-ipv6.conf
 
+Here's a possible setup:
+
+.File `/etc/sysconf.d/90-ipv6.conf`
+----
 net.ipv6.conf.default.forwarding = 0
 net.ipv6.conf.default.proxy_ndp = 0
 net.ipv6.conf.default.autoconf = 0
@@ -488,8 +489,8 @@ net.ipv6.conf.default.accept_ra = 0
 net.ipv6.conf.lo.disable_ipv6 = 0
 ----
 
+.File `/etc/network/interfaces`
 ----
-# /etc/network/interfaces
 (...)
 # Dual stack:
 iface vmbr0 inet static