Fix a deprecation warning with newer Perl that breaks some tests.

--- a/tp/Texinfo/Parser.pm
+++ b/tp/Texinfo/Parser.pm
@@ -5438,12 +5438,12 @@
     }
   } elsif ($command eq 'clickstyle') {
     # REMACRO
-    if ($line =~ /^\s+@([[:alnum:]][[:alnum:]\-]*)({})?\s*/) {
+    if ($line =~ /^\s+@([[:alnum:]][[:alnum:]\-]*)(\{})?\s*/) {
       $args = ['@'.$1];
       $self->{'clickstyle'} = $1
         unless(_ignore_global_commands($self));
       $remaining = $line;
-      $remaining =~ s/^\s+@([[:alnum:]][[:alnum:]\-]*)({})?\s*(\@(c|comment)((\@|\s+).*)?)?//;
+      $remaining =~ s/^\s+@([[:alnum:]][[:alnum:]\-]*)(\{})?\s*(\@(c|comment)((\@|\s+).*)?)?//;
       $has_comment = 1 if (defined($4));
     } else {
       $self->line_error (sprintf($self->__(
lue='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=f206900b92a230ebc7f97c22cf5e79cf0e6b6e46'>refs</a><a class='active' href='/guix/log/README?showmsg=1'>log</a><a href='/guix/tree/README?id=f206900b92a230ebc7f97c22cf5e79cf0e6b6e46'>tree</a><a href='/guix/commit/README?id=f206900b92a230ebc7f97c22cf5e79cf0e6b6e46'>commit</a><a href='/guix/diff/README?id=f206900b92a230ebc7f97c22cf5e79cf0e6b6e46'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/README'>
<input type='hidden' name='id' value='f206900b92a230ebc7f97c22cf5e79cf0e6b6e46'/><input type='hidden' name='showmsg' value='1'/><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=f206900b92a230ebc7f97c22cf5e79cf0e6b6e46&amp;showmsg=1'>root</a>/<a href='/guix/log/README?id=f206900b92a230ebc7f97c22cf5e79cf0e6b6e46&amp;showmsg=1'>README</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/README?id=f206900b92a230ebc7f97c22cf5e79cf0e6b6e46'>Collapse</a>)</th><th class='left'>Author</th></tr>
<tr class='logheader'><td><span title='2021-05-20 01:58:04 +0200'>2021-05-20</span></td><td class='logsubject'><a href='/guix/commit/README?id=c0087d33705f53cc3619a1a43a33602aaecc3a8b'>The #guix channel is hosted by Libera Chat.</a></td><td>Tobias Geerinckx-Rice</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* README (Contact): Update network name.
* ROADMAP: Likewise.
* doc/contributing.texi (Contributing): Likewise.
* doc/guix.texi (After System Installation): Likewise.


</td></tr>
<tr class='logheader'><td><span title='2020-10-23 12:57:20 -0400'>2020-10-23</span></td><td class='logsubject'><a href='/guix/commit/README?id=b5aaa3a4fb985d21e21e2a67f48b52f13ebd4728'>doc: Update README.</a></td><td>Maxim Cournoyer</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* README (Installation): Do not mention installing Guix from Git anymore.
(Building from Git): Add section.


</td></tr>
<tr class='logheader'><td><span title='2020-10-22 22:47:54 -0400'>2020-10-22</span></td><td class='logsubject'><a href='/guix/commit/README?id=503d2bfde08f9bf97bbf430516d2f19faedd4319'>README: Refer to the manual for building from Git.</a></td><td>Maxim Cournoyer</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* README (Installing Guix from Guix): Remove section.
(Installation): For installing from Git, refer to the "Building from Git"
section of the manual and suggest using './pre-inst-env guix pull' rather than
'make install' for installing Guix.


</td></tr>
<tr class='logheader'><td><span title='2020-06-02 18:55:53 +0200'>2020-06-02</span></td><td class='logsubject'><a href='/guix/commit/README?id=c75a80189fc19f6ff8b4c82d1d1801be6763b6d2'>doc: Update README to refer to the manual.</a></td><td>Ludovic Courtès</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* README (Requirements): Refer to the manual.
(Installation): Update URL of the manual.


</td></tr>