[DOCS] 7.16.3 Release Notes

[nastasha-solomon]

Generate the 7.16.3 release notes.

For this release, which is publishing on January 13:

Steps to follow:

1. Check out the 7.16 branch.
2. Run a git fetch origin then git pull to pull in latest changes.
3. Create a branch for the release notes, for example, issue-1380-7.16.3-rn.
4. Add release notes to the correct asciidoc file, which in this case is the 7.16.asciidoc file.
5. Open a PR and switch the base branch (which is the PR will merge into) from main to 7.16.
6. Complete the technical and editorial review, then merge the PR to 7.16.

[nastasha-solomon]

Merged #1381.