XAccessibleText: Add reference to CharacterProperties

Change-Id: I367e0a38ca44b6577e79c1cf2c447a85582ce1e3
Reviewed-on: https://gerrit.libreoffice.org/62632
Tested-by: Jenkins
Reviewed-by: Samuel Mehrbrodt <Samuel.Mehrbrodt@cib.de>

offapi/com/sun/star/accessibility/XAccessibleText.idl

@@ -163,6 +163,8 @@ interface XAccessibleText : ::com::sun::star::uno::XInterface
 
         @throws ::com::sun::star::lang::IndexOutOfBoundsException
             if the index is invalid
+
+        @see CharacterProperties
     */
     sequence<::com::sun::star::beans::PropertyValue>
         getCharacterAttributes (