This is a follow-up to JDK-8332313 to make additional improvements to the contribution guidelines, `CONTRIBUTING.md`, and the code review guidelines, `README-code-reviews.md`.

This list of improvements came out of the review of JDK-8332313. We might eventually split some of these out into their own issue, but that can be decided later.

1. Add some information to CONTRIBUTING.md to describe what makes a good PR.

https://github.com/openjdk/jfx/pull/1455#discussion_r1602072022

In particular, this came up in response the following item for reviewers to check:

* Make sure you understand why there was an issue to begin with, and why/how the proposed PR solves the issue

It was noted that this would be helpful in the section for PR authors. The idea being that a PR author should explain how why / how the PR solve the problem.


2: Update CSR section of code review guidelines

https://github.com/openjdk/jfx/pull/1455#discussion_r1602095257
https://github.com/openjdk/jfx/pull/1455#discussion_r1602105550

Improve the section in the review guidelines on creating a CSR.


3. Update the section on low-impact fixes in the code review guidelines

https://github.com/openjdk/jfx/pull/1455#discussion_r1602085558

We should indicate that the regression and compatibility impact are among the main things to consider when making the determination about whether a fix needs two reviewers or not.


4. Add a recommendation to CONTRIBUTING that it's a good idea to search for JBS issues similar/linked to the one being targeted.

https://github.com/openjdk/jfx/pull/1455#discussion_r1602134914


5. Consider making a list of area experts available, probably not in the repo, but possibly linked from the code review guidelines.

https://github.com/openjdk/jfx/pull/1455#discussion_r1602145807


6. Add information to the code review guidelines on what to look for when reviewing new API.

https://github.com/openjdk/jfx/pull/1455#discussion_r1605797980


7. Consider having a formal recommended order for imports, and update the contribution guidelines.

https://github.com/openjdk/jfx/pull/1455#discussion_r1602895839

The lack of a recommended order for imports, along with the fact that different IDEs do it differently by default means that some PRs will have a lot of changes in the imports that can later lead to merge conflicts. If we do anything about this, we likely need to split this out into its own issue.