findreplacedialog: Set a11y role of hint text to static

Since this is not a label for another widget, but some text that screen
readers should speak.

Change-Id: Iddc2840e60c8a55caf2e6581831024e2658e084e
Reviewed-on: https://gerrit.libreoffice.org/59668
Tested-by: Jenkins
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

svx/uiconfig/ui/findreplacedialog.ui

@@ -167,6 +167,9 @@
                             <property name="wrap">True</property>
                             <property name="ellipsize">end</property>
                             <property name="xalign">0</property>
+                            <accessibility>
+                              <role type="static"/>
+                            </accessibility>
                           </object>
                           <packing>
                             <property name="left_attach">1</property>