src/*.pod: make head4 text italic for better term view

src/40_install.pod

@@ -81,13 +81,13 @@ Using L<parted(8)> utility we can create all required partitions.
     (parted) name 2 luks
     (parted) quit
 
-=head4 Boot partition filesystem
+=head4 I<Boot partition filesystem>
 
 Create a FAT32 filesystem for the first (efiboot) partition:
 
     # mkfs.vfat -F32 /dev/sda1
 
-=head4 Encrypt LUKS partition
+=head4 I<Encrypt LUKS partition>
 
 Encrypt the second (luks) partition with LUKS and open the LUKS
 device:
@@ -97,15 +97,15 @@ device:
 
 =head3 B<LVM inside LUKS device>
 
-=head4 Create the physical volume
+=head4 I<Create the physical volume>
 
     # pvcreate /dev/mapper/crypt
 
-=head4 Create the volume group
+=head4 I<Create the volume group>
 
     # vgcreate zpln /dev/mapper/crypt
 
-=head4 Create the logical volume
+=head4 I<Create the logical volume>
 
 This is a quite simple logical volumes scheme used in this handbook.
 
@@ -183,7 +183,7 @@ won't pollute LiveCD RAM:
     # cd /mnt
     # wget -c https://github.com/zeppe-lin/pkgsrc-core/releases/download/v0.99/rootfs-v0.99-x86_64.tar.xz{,.sig}
 
-=head4 Signature verification
+=head4 I<Signature verification>
 
 It's optional but highly recommended to verify rootfs signature:
 
@@ -332,7 +332,7 @@ and enable the collections you cloned.  By default, only C<core>
 collection is enabled.  Also, you may like to edit F</etc/pkgmk.conf>
 (see L<pkgmk.conf(5)> for more information).
 
-=head4 Update the core packages and configuration files
+=head4 I<Update the core packages and configuration files>
 
 B<Note>: Starting from version C<6.0>, C<pkgutils> has broken backward
 compatibility when generating footprint files.  So, at the beginning
@@ -365,7 +365,7 @@ and/or B<wpa_supplicant> RC scripts.
 There is at least two ways to install the kernel: as a package and
 manually.  Let's look at each method.
 
-=head4 Install the kernel package
+=head4 I<Install the kernel package>
 
 C<system> pkgsrc collection provides a package with the kernel and
 non-free firmware:
@@ -388,7 +388,7 @@ for more information about package locking.
 If you installed the kernel package through a package manager, you can
 jump over the next paragraph, to the L</"Prepare initramfs image">.
 
-=head4 Install the kernel manually
+=head4 I<Install the kernel manually>
 
 Since the L<pkgman(1)> build the package that contains only the
 binaries (kernel and modules), you may want to build your own kernel.

src/52_package_system:_using_the_package_system.pod

@@ -132,7 +132,7 @@ referring to the files in the package, not the files on the disk.
 
 See L<pkgadd.conf(5)> for more information.
 
-=head4 Rejected files
+=head4 I<Rejected files>
 
 If L<pkgadd(8)> finds that a specific file should not be upgraded, it
 will install it under F</var/lib/pkg/rejected/>.  Files in this
@@ -263,7 +263,7 @@ _
 
 =end html
 
-=head4 List installed packages and their version
+=head4 I<List installed packages and their version>
 
     $ pkginfo -i
     audiofile 0.2.3-1
@@ -274,7 +274,7 @@ _
     zip 2.3-1
     zlib 1.1.4-1
 
-=head4 List files in PACKAGE or FILE
+=head4 I<List files in PACKAGE or FILE>
 
     $ pkginfo -l bash
     bin/
@@ -298,14 +298,14 @@ _
     usr/share/man/man1/fgrep.1.gz
     usr/share/man/man1/grep.1.gz
 
-=head4 List owners of files matching F<bin/ls>
+=head4 I<List owners of files matching F<bin/ls>>
 
     $ pkginfo -o bin/ls
     e2fsprogs  usr/bin/lsattr
     fileutils  bin/ls
     modutils   sbin/lsmod
 
-=head4 Print footprint for file
+=head4 I<Print footprint for file>
 
     $ pkginfo -f xorg-xkill#1.0.5-1.pkg.tar.gz
     drwxr-xr-x      root/root       usr/

src/53_package_system:_pkgman.pod

@@ -9,7 +9,7 @@ mentioned below) as well as some overlap with B<pkgutils> features.
 
 Some examples of pkgman's functionality and use are as follows:
 
-=head4 Listing installed packages
+=head4 I<Listing installed packages>
 
     $ pkgman list
     acl
@@ -26,7 +26,7 @@ Some examples of pkgman's functionality and use are as follows:
     attr 2.5.1-1: Extended attribute support library for ACL support
     [...]
 
-=head4 Querying information about a package source
+=head4 I<Querying information about a package source>
 
     $ pkgman info acl
     Name:         acl
@@ -37,7 +37,7 @@ Some examples of pkgman's functionality and use are as follows:
     URL:          http://savannah.nongnu.org/projects/acl
     Dependencies: attr
 
-=head4 Searching for packages sources by name
+=head4 I<Searching for packages sources by name>
 
     $ pkgman search -vv glibc
     -- search ([i] = installed)
@@ -49,7 +49,7 @@ Some examples of pkgman's functionality and use are as follows:
     [i] glib 2.70.1-1: Common C routines used by Gtk+ and other libs
     [i] glibc 2.32-5: GNU C Library
 
-=head4 Searching for packages sources by words in their description
+=head4 I<Searching for packages sources by words in their description>
 
     $ pkgman dsearch -vv archive
     -- search ([i] = installed)
@@ -58,7 +58,7 @@ Some examples of pkgman's functionality and use are as follows:
     [ ] unrar 6.0.7-1: Extracts RAR archives
     [ ] zip 3.0-1: Compression and file packaging/archive utility
 
-=head4 Viewing dependency lists
+=head4 I<Viewing dependency lists>
 
     $ pkgman dep bash
     readline
@@ -73,7 +73,7 @@ Some examples of pkgman's functionality and use are as follows:
     [i]   readline 8.1.1-1: Lets users edit command lines as they are typed in
     [i]     ncurses 6.3-1: System V Release 4.0 curses emulation library
 
-=head4 Installing packages
+=head4 I<Installing packages>
 
     $ pkgman install --deps xterm
 
@@ -106,7 +106,7 @@ already installed package(s).  It just ignores the package and
 installs next in the listed order.  At the end of the installation
 procedure, all skipped packages will be in the report.
 
-=head4 Viewing and updating outdated packages
+=head4 I<Viewing and updating outdated packages>
 
 Since the packages sources for Zeppe-Lin are distributed via
 L<git(1)>, the first thing to do is to update the C<pkgsrc>

src/61_pkgsrc_system:_introduction.pod

@@ -30,7 +30,7 @@ binary packages.
 Packages' sources are organized in so-called collections.  There are
 five different layers (or five categories) of packages.
 
-=head4 L<core|https://github.com/zeppe-lin/pkgsrc-core>
+=head4 I<< L<core|https://github.com/zeppe-lin/pkgsrc-core> >>
 
 This collection contains build scripts and files for the packages
 required to create a basic system, on the basis of which you can build
@@ -47,27 +47,27 @@ L<pkgmaint|https://github.com/zeppe-lin/pkgmaint> and corresponding
 B<system/pkgmaint> package for various package maintaining utilities.
 It will not be superfluous to mention L<revdep(1)>.
 
-=head4 L<system|https://github.com/zeppe-lin/pkgsrc-system>
+=head4 I<< L<system|https://github.com/zeppe-lin/pkgsrc-system> >>
 
 This collection contains build scripts and files for the packages
 required for minimal installation on real hardware: boot loader,
 filesystem utilities, hw-monitors, servers, and so on.  Packages in
 this collection depend B<only> on the C<core> pkgsrc collection.
 
-=head4 L<xorg|https://github.com/zeppe-lin/pkgsrc-xorg>
+=head4 I<< L<xorg|https://github.com/zeppe-lin/pkgsrc-xorg> >>
 
 This collection contains build scripts and files for the packages
 required for X Window System applications.  Packages in this
 collection depend on the C<system> collection.
 
-=head4 L<desktop|https://github.com/zeppe-lin/pkgsrc-desktop>
+=head4 I<< L<desktop|https://github.com/zeppe-lin/pkgsrc-desktop> >>
 
 This collection contains build scripts and files for the packages
 typically used on a desktop: web browser, music/video player, file
 manager, chat messenger, etc.  Packages in this collection depend on
 the C<xorg> collection.
 
-=head4 L<stuff|https://github.com/zeppe-lin/pkgsrc-stuff>
+=head4 I<< L<stuff|https://github.com/zeppe-lin/pkgsrc-stuff> >>
 
 This collection contains build scripts and files for the packages that
 do not fit into the above categories.  Packages in this collection may