doclint errors about missing accessibility support in HTML files.

Some improvements in doclint have identified several doclint accessibility related HTML errors in the html files in the desktop module.

/Volumes/J2GWork/jdk/jdk.ref/open/src/java.desktop/share/classes/java/awt/doc-files/DesktopProperties.html:81: error: no summary or caption for table
</table>
^
/Volumes/J2GWork/jdk/jdk.ref/open/src/java.desktop/share/classes/javax/imageio/metadata/doc-files/tiff_metadata.html:377: error: no summary or caption for table
</table>
^
/Volumes/J2GWork/jdk/jdk.ref/open/src/java.desktop/share/classes/javax/imageio/metadata/doc-files/tiff_metadata.html:893: error: no summary or caption for table
</table>
^
/Volumes/J2GWork/jdk/jdk.ref/open/src/java.desktop/share/classes/javax/swing/plaf/synth/doc-files/componentProperties.html:1345: error: no summary or caption for table
</table>
^
4 errors