man: several more assorted fixes

Continuation of 4ebbb5bfe8.
Closes #35307.

man/importctl.xml

@@ -128,7 +128,8 @@
 
         <para>If <option>-keep-download=yes</option> is specified the image will be downloaded and stored in
         a read-only subvolume/directory in the image directory that is named after the specified URL and its
-        HTTP etag. A writable snapshot is then taken from this subvolume, and named after the specified local
+        HTTP etag (see <ulink url="https://en.wikipedia.org/wiki/HTTP_ETag">HTTP ETag</ulink> for more
+        information). A writable snapshot is then taken from this subvolume, and named after the specified local
         name. This behavior ensures that creating multiple instances of the same URL is efficient, as
         multiple downloads are not necessary. In order to create only the read-only image, and avoid creating
         its writable snapshot, specify <literal>-</literal> as local name.</para>

man/pam_systemd_loadkey.xml

@@ -28,7 +28,9 @@
     <title>Description</title>
 
     <para><command>pam_systemd_loadkey</command> reads a NUL-separated password list from the kernel keyring,
-    and sets the last password in the list as the PAM authtok.</para>
+    and sets the last password in the list as the PAM authtok, which can be used by e.g.
+    <citerefentry project='man-pages'><refentrytitle>pam_get_authtok</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+    </para>
 
     <para>The password list is supposed to be stored in the "user" keyring of the root user,
     by an earlier call to

man/run0.xml

@@ -61,7 +61,10 @@
     <literal>systemd-run0</literal> PAM stack.</para>
 
     <para>Note that <command>run0</command> is implemented as an alternative multi-call invocation of
-    <citerefentry><refentrytitle>systemd-run</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
+    <citerefentry><refentrytitle>systemd-run</refentrytitle><manvolnum>1</manvolnum></citerefentry>. That is,
+    <command>run0</command> is a symbolic link to <command>systemd-run</command> executable file, and it
+    behaves as <command>run0</command> if it is invoked through the symbolic link, otherwise behaves as
+    <command>systemd-run</command>.</para>
   </refsect1>
 
   <refsect1>

man/systemd-rfkill.service.xml

@@ -41,8 +41,10 @@
   <refsect1>
     <title>Kernel Command Line</title>
 
-    <para><filename>systemd-rfkill</filename> understands the
-    following kernel command line parameter:</para>
+    <para>
+      <command>systemd-rfkill</command> understands the following kernel command line parameter. See also
+      <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
+    </para>
 
     <variablelist class='kernel-commandline-options'>
       <varlistentry>

man/ukify.xml

@@ -394,9 +394,9 @@
           <listitem><para>SBAT metadata associated with the UKI or addon. SBAT policies are useful to revoke
           whole groups of UKIs or addons with a single, static policy update that does not take space in
           DBX/MOKX. If not specified manually, a default metadata entry consisting of
-          <literal>uki,1,UKI,uki,1,https://uapi-group.org/specifications/specs/unified_kernel_image/</literal>
+          <programlisting>uki,1,UKI,uki,1,https://uapi-group.org/specifications/specs/unified_kernel_image/</programlisting>
           for UKIs and
-          <literal>uki-addon,1,UKI Addon,addon,1,https://www.freedesktop.org/software/systemd/man/latest/systemd-stub.html</literal>
+          <programlisting>uki-addon,1,UKI Addon,addon,1,https://www.freedesktop.org/software/systemd/man/latest/systemd-stub.html</programlisting>
           for addons will be used, to ensure it is always possible to revoke them. For more information on
           SBAT see <ulink url="https://github.com/rhboot/shim/blob/main/SBAT.md">Shim documentation</ulink>.
           </para>