Add search and clear icons to the filter entry

tools/editors/resource-browser/glade/resource-browser.glade

@@ -23,6 +23,10 @@
             <property name="can_focus">True</property>
             <property name="invisible_char">●</property>
             <property name="caps_lock_warning">False</property>
+            <property name="primary_icon_name">edit-find-symbolic</property>
+            <property name="secondary_icon_name">edit-clear-symbolic</property>
+            <property name="primary_icon_activatable">False</property>
+            <property name="primary_icon_sensitive">False</property>
             <property name="placeholder_text">Find resource</property>
             <signal name="changed" handler="on_filter_entry_text_changed" swapped="no"/>
           </object>