[glib: 1/2] docs: Add --delete option to gio-tool attributes documentation

[Matthias Clasen <matthiasc src gnome org>]

commit ea0617e993945294b994f38d6e7df10ba36ee1b4
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Fri Aug 5 22:23:49 2022 +0200

    docs: Add --delete option to gio-tool attributes documentation
    
    It was added via !2845 but not documented.

 docs/reference/gio/gio.xml | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/docs/reference/gio/gio.xml b/docs/reference/gio/gio.xml
index 532bf9064f..1805b2790a 100644
--- a/docs/reference/gio/gio.xml
+++ b/docs/reference/gio/gio.xml
@@ -681,6 +681,10 @@
                   <para>If the type is not specified, <literal>string</literal> is assumed.</para>
                 </listitem>
               </varlistentry>
+              <varlistentry>
+                <term><option>-d</option>, <option>--delete</option></term>
+                <listitem><para>Unsets an attribute (same as setting it's type to 
<literal>unset</literal>).</para></listitem>
+              </varlistentry>
               <varlistentry>
                 <term><option>-n</option>, <option>--nofollow-symlinks</option></term>
                 <listitem><para>Don’t follow symbolic links.</para></listitem>