Update docs to Discussions (#4503)

docs/i3-pod2html

@@ -83,7 +83,7 @@ $parser->html_header_after_title(
 			<ul id="nav">
 				<li><a style="border-bottom: 2px solid #fff" href="/docs">Docs</a></li>
 				<li><a href="/screenshots">Screens</a></li>
-				<li><a href="https://www.reddit.com/r/i3wm/">FAQ</a></li>
+				<li><a href="https://www.github.com/i3/i3/discussions">Get Help</a></li>
 				<li><a href="/contact">Contact</a></li>
 				<li><a href="https://bugs.i3wm.org/">Bugs</a></li>
 			</ul>

docs/userguide

@@ -3,9 +3,9 @@ i3 User’s Guide
 Michael Stapelberg <michael@i3wm.org>
 
 This document contains all the information you need to configure and use the i3
-window manager. If it does not, please check https://www.reddit.com/r/i3wm/
-first, then contact us on IRC (preferred) or post your question(s) on the
-mailing list.
+window manager. If it does not you can https://i3wm.org/contact/[contact us] on
+https://github.com/i3/i3/discussions[GitHub Discussions], IRC, or the mailing
+list.
 
 == Default keybindings