Accessibility issues in java.base docs

1.The following docs don't have main landmarks. See https://www.w3.org/TR/WCAG20-TECHS/ARIA11.htm and all content should be contained in a landmark region.

docs/api/java.base/java/net/doc-files/net-properties.html
docs/api/java.base/java/util/doc-files/coll-overview.html
docs/api/java.base/java/util/doc-files/coll-reference.html
docs/api/java.base/java/util/doc-files/coll-index.html
docs/api/java.base/java/util/doc-files/coll-designfaq.html
docs/api/java.base/java/lang/doc-files/threadPrimitiveDeprecation.html
docs/api/java.base/java/lang/doc-files/ValueBased.html

2. Low contrast
docs/api/java.base/java/time/chrono/HijrahChronology.html
<code>Locale</code> Element has insufficient color contrast of 4.35 (foreground color: #4a6782- background color: #dddddd- font size: 10.5pt- font weight: bold). Expected contrast ratio of 4.5:1 html > body > [role="main"] > .contentContainer > .description > ul > li > .block > table > thead > tr > th:nth-child(3) > a > code


3. Heading order invalid
docs/api/java.base/java/time/temporal/package-summary.html <h3>Fields and Units</h3>
docs/api/java.base/java/time/chrono/package-summary.html <h3>Example</h3>
docs/api/java.base/java/time/zone/package-summary.html <h3>Package specification</h3>
docs/api/java.base/java/time/package-summary.html <h3>Dates and Times</h3>
docs/api/java.base/java/time/format/package-summary.html <h3>Package specification</h3>
docs/api/java.base/java/lang/package-summary.html <h3>Character Encodings</h3>
docs/api/java.base/java/nio/file/package-summary.html <h3><a id="links">Symbolic Links</a></h3>

4. Broken link <a href="#feature">feature version number</a>
http://hg.openjdk.java.net/jdk/jdk/file/af37d9997bd6/src/java.base/share/classes/java/lang/Runtime.java#l1192