[enhanced-enums] RFR: Merge master [v3]

[J.Duke]

> Hi all,
> 
> this is an _automatically_ generated pull request to notify you that there are 76 commits from the branch `master`that
> can **not** be merged into the branch `enhanced-enums`:
> The following file contains merge conflicts:
> 
> - .jcheck/conf
> 
> All Committers in this [project](https://openjdk.java.net/census#Optional[amber]) have access to my [personal
> fork](https://github.com/openjdk-bot/amber) and can therefore help resolve these merge conflicts (you may want to
> coordinate who should do this). The following paragraphs will give an example on how to solve these merge conflicts and
> push the resulting merge commit to this pull request. The below commands should be run in a local clone of your
> [personal fork](https://wiki.openjdk.java.net/display/skara#Skara-Personalforks) of the
> [openjdk/amber](https://github.com/openjdk/amber) repository.  # Ensure target branch is up to date $ git checkout
> enhanced-enums $ git pull https://github.com/openjdk/amber enhanced-enums
> 
> # Fetch and checkout the branch for this pull request
> $ git fetch https://github.com/openjdk-bot/amber +66:openjdk-bot-66
> $ git checkout openjdk-bot-66
> 
> # Merge the target branch
> $ git merge enhanced-enums
> 
> When you have resolved the conflicts resulting from the `git merge` command above, run the following commands to create
> a merge commit:
> $ git add paths/to/files/with/conflicts
> $ git commit -m 'Merge master'
> 
> 
> When you have created the merge commit, run the following command to push the merge commit to this pull request:
> 
> $ git push https://github.com/openjdk-bot/amber openjdk-bot-66:66
> 
> _Note_: if you are using SSH to push commits to GitHub, then change the URL in the above `git push` command accordingly.
> 
> Thanks,
> J. Duke

J. Duke has updated the pull request incrementally with 89 additional commits since the last revision:

 - manual merge
 - Merge master
 - Automatic merge of master into sealed-types
 - Automatic merge of master into sealed-types
 - Automatic merge of master into sealed-types
 - 8248185: fix the javadoc for Class::isSealed
 - Automatic merge of master into sealed-types
 - no sealed annotations
 - Automatic merge of master into sealed-types
 - Automatic merge of master into sealed-types
 - ... and 79 more: https://git.openjdk.java.net/amber/compare/b0f9619a...053f47d0

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

Changes:
  - all: https://git.openjdk.java.net/amber/pull/51/files
  - new: https://git.openjdk.java.net/amber/pull/51/files/b0f9619a..053f47d0

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=amber&pr=51&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=amber&pr=51&range=01-02

  Stats: 38 lines in 6 files changed: 32 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/amber/pull/51.diff
  Fetch: git fetch https://git.openjdk.java.net/amber pull/51/head:pull/51

PR: https://git.openjdk.java.net/amber/pull/51