Small refinements and fixes to new release process doc

[nsoranzo]

Follow-up on #17680 .

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[dannon]

@nsoranzo I pushed a tweak to address #18167, feel free to drop it though.

[nsoranzo]

@dannon Unfortunately, SECURITY,md is one of the Procedure Documents covered by https://docs.galaxyproject.org/en/master/project/organization.html

[dannon]

@nsoranzo Argh, so it is. I'll pop that back out of this and make a separate PR.

[nsoranzo]

Thanks!