RFR: 8308694: Clarify reversed() default methods' implementation requirements [v4]

[Stuart Marks]

> Can I get a preliminary review of the wording for Deque.reversed()? If the text is good, I'll make corresponding changes to the implSpecs of the other reversed() default methods, namely those in List, SortedMap, and SortedSet and then file the CSR.

Stuart Marks has updated the pull request incrementally with two additional commits since the last revision:

 - Update docs for reversed() method of List, SortedMap, SortedSet.
 - Slight rewording of the original paragraph in Deque.

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/14504/files
  - new: https://git.openjdk.org/jdk/pull/14504/files/c8a69ee7..b97e6022

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14504&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14504&range=02-03

  Stats: 27 lines in 4 files changed: 18 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/14504.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14504/head:pull/14504

PR: https://git.openjdk.org/jdk/pull/14504