@executionStrategy javadoc annotation is not recognized, but @attainAlways is (which is not documented)

• Testcase included:

  yes

/**
 * @goal test
 * @executionStrategy always
 */

generates

<mojo>
      <goal>test</goal>
      <executionStrategy>once-per-session</executionStrategy>
    </mojo>

but

/**
 * @goal test
 * @attainAlways
 */

does generate

<mojo>
      <goal>test</goal>
      <executionStrategy>always</executionStrategy>
    </mojo>

either both forms should be supported and documented, or only @executionStrategy since it is documented in http://maven.apache.org/developers/mojo-api-specification.html for a long time
(notice: I suppose nobody tried to use it...)