Adjust documentation for Sphinx 4.0.

Discussed upstream at <https://github.com/ganeti/ganeti/pull/1615>.

diff --git a/doc/index.rst b/doc/index.rst
--- a/doc/index.rst
+++ b/doc/index.rst
@@ -119,7 +119,6 @@ Draft designs
    design-hotplug.rst
    design-internal-shutdown.rst
    design-kvmd.rst
-   design-location.rst
    design-linuxha.rst
    design-location.rst
    design-lu-generated-jobs.rst
diff --git a/lib/build/shell_example_lexer.py b/lib/build/shell_example_lexer.py
--- a/lib/build/shell_example_lexer.py
+++ b/lib/build/shell_example_lexer.py
@@ -79,4 +79,4 @@ class ShellExampleLexer(RegexLexer):
 
 
 def setup(app):
-  app.add_lexer("shell-example", ShellExampleLexer())
+  app.add_lexer("shell-example", ShellExampleLexer)
alue='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=a84586dad60fe28c3b1832c197f1e0b1f6f12721'>refs</a><a class='active' href='/guix/log/gnu/services/security.scm'>log</a><a href='/guix/tree/gnu/services/security.scm?id=a84586dad60fe28c3b1832c197f1e0b1f6f12721'>tree</a><a href='/guix/commit/gnu/services/security.scm?id=a84586dad60fe28c3b1832c197f1e0b1f6f12721'>commit</a><a href='/guix/diff/gnu/services/security.scm?id=a84586dad60fe28c3b1832c197f1e0b1f6f12721'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/services/security.scm'>
<input type='hidden' name='id' value='a84586dad60fe28c3b1832c197f1e0b1f6f12721'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=a84586dad60fe28c3b1832c197f1e0b1f6f12721'>root</a>/<a href='/guix/log/gnu?id=a84586dad60fe28c3b1832c197f1e0b1f6f12721'>gnu</a>/<a href='/guix/log/gnu/services?id=a84586dad60fe28c3b1832c197f1e0b1f6f12721'>services</a>/<a href='/guix/log/gnu/services/security.scm?id=a84586dad60fe28c3b1832c197f1e0b1f6f12721'>security.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/services/security.scm?id=a84586dad60fe28c3b1832c197f1e0b1f6f12721&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-04-02 12:35:30 +0200'>2023-04-02</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=0fbb356714f4ae3ea18e4997131a0e1746cc923c'>services: replace bare serializers with (serializer ...)</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/home/services/shells.scm
(home-zsh-configuration)[environment-variables]: Use (serializer ...).
(home-bash-configuration)[aliases, environment-variables]: Likewise.
(home-fish-configuration)[abbreviations, aliases]
[environment-variables]: Likewise.
* gnu/services/audio.scm (mpd-configuration)[music-dir, playlist-dir]
[endpoints, address, inputs, archive-plugins, input-cache-size]
[decoders, filters, playlist-plugins]: Likewise.
* gnu/services/linux.scm (fstrim-configuration)[extra-arguments]:
Likewise.
* gnu/services/security.scm (fail2ban-jail-configuration)[backend]
[log-encoding, extra-content]: Likewise.
* tests/services/configuration.scm: Update tests.
("serialize-configuration [deprecated]"): New test.

Signed-off-by: Liliana Marie Prikler &lt;liliana.prikler@gmail.com&gt;
</span></span></td><td>Bruno Victal</td></tr>
<tr><td><span title='2023-01-10 10:47:27 -0500'>2023-01-10</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=dc403ec7f15cdb94a43654a941b25894cff707c7'>gnu: services: Fix fail2ban configuration serialization.</a><span class='msg-avail'>...<span class='msg-tooltip'>This fixes a regression from 543d971ed2a1d9eb934af1f51930741d7cc4e7ef whereby
match-lambda due to configuration field reordering.

* gnu/services/security.scm:
[serialize-fail2ban-ignore-cache-configuration]: Switch to match-record.
[serialize-fail2ban-jail-filter-configuration]: Switch to match-record.
[serialize-fail2ban-jail-action-configuration]: Switch to match-record.

Signed-off-by: Maxim Cournoyer &lt;maxim.cournoyer@gmail.com&gt;
</span></span></td><td>muradm</td></tr>
<tr><td><span title='2022-12-06 17:49:50 +0100'>2022-12-06</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=a420b4f34e7449319f6ec73301ffb932845b66d6'>services: fail2ban: Start server in the foreground.</a><span class='msg-avail'>...<span class='msg-tooltip'>Previously, we were passing '-b', thereby starting the server in the
background.  Consequently the 'start' method could complete before the
server was ready to accept connections on its socket, leading to
non-deterministic test failures.

Reported by Mathieu Othacehe &lt;othacehe@gnu.org&gt;.

* gnu/services/security.scm (fail2ban-shepherd-service): Change
FAIL2BAN-ACTION to invoke 'fail2ban-client'.
Change 'start' method to use 'make-forkexec-constructor'; start the
server in the foreground with '-f' and pass '-x' to force execution of
the server, as done upstream in 'fail2ban.service.in'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-12-06 17:07:46 +0100'>2022-12-06</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=a508b5c7785bcd040c5a9e890be71ccd97f198fb'>services: fail2ban: Remove unnecessary Shepherd 'modules' field.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/security.scm (fail2ban-shepherd-service): Remove
unnecessary 'modules' field.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-12-06 17:07:12 +0100'>2022-12-06</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=e45c83c3979c2554119fafdee7bb204d27e138b5'>services: fail2ban: 'stop' returns #f when the dameon is stopped.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/security.scm (fail2ban-shepherd-service): Change
FAIL2BAN-ACTION to return an 'invoke' gexp.
Adjust the shepherd 'start' and 'stop' fields accordingly.  Have 'stop'
return #f on success.
</span></span></td><td>Ludovic Courtès</td></tr>