8185994: Fix a11y and HTML issues in the java.base/java.io and java.base/java.nio packages
Reviewed-by: bpb, smarks

8181156: html5 issues in java.base javadoc
Reviewed-by: alanb

8181290: Invalid HTML 5 in core-libs docs
Reviewed-by: mchung, lancea

8133459: replace <tt> tags (obsolete in html5) in java.nio docs
Reviewed-by: lancea

8054834: Modular Source Code
Reviewed-by: alanb, chegar, ihse, mduigou
Contributed-by: alan.bateman@oracle.com, alex.buckley@oracle.com, chris.hegarty@oracle.com, erik.joelsson@oracle.com, jonathan.gibbons@oracle.com, karen.kinnear@oracle.com, magnus.ihse.bursie@oracle.com, mandy.chung@oracle.com, mark.reinhold@oracle.com, paul.sandoz@oracle.com