Add some missing @since tags

...for constants introduced with 4917430c1c
"tdf#116542 a11y: introduce STATIC role" and
947fe0d89d "tdf#119788 tdf#117173 add
accessibility NOTIFICATION role", resp.

Change-Id: I1533f3bfcac5e7014078dd891dc05571f1186bb1
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/140587
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

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

@@ -734,6 +734,8 @@ constants AccessibleRole
            label.</p>
 
         <p>See also LABEL and TEXT.</p>
+
+        @since LibreOffice 6.2
     */
     const short STATIC = 86;
 
@@ -741,6 +743,8 @@ constants AccessibleRole
 
         <p>An object that presents information to the user when the SHOWING state change event is
            fired for the object.</p>
+
+        @since LibreOffice 7.5
     */
     const short NOTIFICATION = 87;