add attention about missing network on irssi<=1.2

New-users.html

@@ -393,6 +393,10 @@
 </pre></div>
 </div>
 <p>You should see several messages scroll by. After a while, you should be connected to the Libera Chat network.</p>
+<div class="admonition attention">
+<p class="admonition-title">Attention</p>
+<p>Irssi version 1.2 or older may be lacking the liberachat network entry. See <a class="reference external" href="https://github.com/shabble/irssi-docs/wiki/liberachat">https://github.com/shabble/irssi-docs/wiki/liberachat</a> for how to add it.</p>
+</div>
 <section id="nickname-registration">
 <h3>Nickname registration<a class="headerlink" href="#nickname-registration" title="Permalink to this headline"> </a></h3>
 <p>Many IRC networks (but not all) offer a way to register a user account. Sometimes (but not on all networks) the account registration also includes reserving a nick for you. <em>How</em> to register also differs by network. Some <em>channels</em> only allow users with registered accounts to join them, so it may be very important for you to register a user account.</p>

_sources/New-users.md.txt

@@ -54,6 +54,10 @@ To connect to one of the networks in the list, type `/connect networkname`, for
 
 You should see several messages scroll by. After a while, you should be connected to the Libera Chat network.
 
+:::{attention}
+Irssi version 1.2 or older may be lacking the liberachat network entry. See https://github.com/shabble/irssi-docs/wiki/liberachat for how to add it.
+:::
+
 ### Nickname registration
 
 Many IRC networks (but not all) offer a way to register a user account. Sometimes (but not on all networks) the account registration also includes reserving a nick for you. *How* to register also differs by network. Some _channels_ only allow users with registered accounts to join them, so it may be very important for you to register a user account.