Merge pull request #1929 from flatpak/autoprune-unless-docs

doc: Document the autoprune-unless metadata key

doc/flatpak-metadata.xml

@@ -610,6 +610,16 @@
                         branch in 0.8.3.
                     </para></listitem>
                 </varlistentry>
+                <varlistentry>
+                    <term><option>autoprune-unless</option> (string)</term>
+                    <listitem><para>
+                        A condition that must be false for the extension to be considered unused when
+                        pruning. For example, <command>flatpak uninstall --unused</command> uses
+                        this information. The only currently recognized value is active-gl-driver,
+                        which is true if the name of the active GL driver matches the extension
+                        point basename. Available since 0.11.8.
+                    </para></listitem>
+                </varlistentry>
                 <varlistentry>
                     <term><option>enable-if</option> (string)</term>
                     <listitem><para>