idl: change since from 6.2 to 6.1 for new status bar property

New property introduced in d77f8eef
expected to be backported to 6.1

Change-Id: I6486fa0f42adcd39c9929f4d90b7310e22d851c6
Reviewed-on: https://gerrit.libreoffice.org/56685Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Tested-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

offapi/com/sun/star/ui/ItemStyle.idl

@@ -153,7 +153,7 @@ constants ItemStyle
     /** marks always visible element which can not be removed when statusbar
         width is not sufficient.
 
-        @since LibreOffice 6.2
+        @since LibreOffice 6.1
     */
     const short MANDATORY = 4096;
 };

offapi/com/sun/star/ui/XStatusbarItem.idl

@@ -64,7 +64,7 @@ interface XStatusbarItem
             </li>
             <li>com::sun::star::ui::ItemStyle::AUTO_SIZE</li>
             <li>com::sun::star::ui::ItemStyle::OWNER_DRAW</li>
-            <li>com::sun::star::ui::ItemStyle::MANDATORY (@since LibreOffice 6.2)</li>
+            <li>com::sun::star::ui::ItemStyle::MANDATORY (@since LibreOffice 6.1)</li>
         </ul>
 
         @see com::sun::star::ui::ItemStyle