RFR: JDK-8186466: Fix accessibility and other minor issues in java.base

[Martin Buchholz]

Thanks as usual for the modern html lessons.  Looks good.

Things I wonder about:
- I expected to find scope= attributes in BlockingDeque.java tables. TIL
about colgroup and rowgroup.  (or does headers=... make that redundant?)
- I see "font-style: italic" but that seems rather low-level and I expected
something higher level.
- I was surprised by

 178  *    <th id="peek" style="font-weight:normal;
text-align:left">{@link #peek() peek()}</th> 179  *    <td
headers="Examine BDeque peek">{@link #peekFirst() peekFirst()}</td>


because these two cells are "parallel" and so I expected them to have
similar definitions.  I can see they are "related" and the headers= makes
that clear, but it still feels slightly wrong to make one of them a <th>
and the other a <td>.