docs/Releases: update process documentation.

- Note that Homebrew/homebrew-core CI jobs should complete successfully
  before creating a release
- No code changes only required for 4 hours, 24 hours is a bit
  excessive/unrealistic
- Note that commented `odeprecated` code should be uncommented
- TinyLetter emails are no longer required (MailChimp does so
  automatically from the RSS feed)
- Note that `brew release` will output the major/minor blog post content
  (after #10499 is merged) instead of referencing the now-deprecated
  `brew release-notes`
- Note why you should not create a release on older `master` commits and
  provide an alternate process to handle this case
- Various style tweaks

docs/Releases.md

@@ -1,18 +1,21 @@
 # Releases
 
 Since Homebrew 1.0.0 most Homebrew users (those who haven't run a `dev-cmd` or
-set `HOMEBREW_DEVELOPER=1`) require tags on the [Homebrew/brew repository](https://github.com/homebrew/brew)
+set `HOMEBREW_DEVELOPER=1` which is ~99.9% based on analytics data) require tags
+on the [Homebrew/brew repository](https://github.com/homebrew/brew)
 in order to get new versions of Homebrew. There are a few steps in making a new
 Homebrew release:
 
 1. Check the [Homebrew/brew pull requests](https://github.com/homebrew/brew/pulls),
    [issues](https://github.com/homebrew/brew/issues),
-   [Homebrew/core issues](https://github.com/homebrew/homebrew-core/issues) and
+   [Homebrew/homebrew-core issues](https://github.com/homebrew/homebrew-core/issues) and
    [Homebrew/discussions (forum)](https://github.com/homebrew/discussions/discussions) to see if there is
    anything pressing that needs to be fixed or merged before the next release.
    If so, fix and merge these changes.
-2. Ensure that no code changes have happened for at least a couple of hours (ideally 24 hours)
-   and that you are confident there are no major regressions on the current `master`
+2. Ensure that no code changes have happened for at least a couple of hours (ideally 4 hours),
+   at least one Homebrew/homebrew-core pull request CI job has completed successfully,
+   checked the state of the Homebrew/brew `master` CI job (i.e. main jobs green or green after rerunning),
+   and that you are confident there are no major regressions on the current `master`,
    branch.
 3. Run `brew release` to create a new draft release. For major or minor version bumps,
    pass `--major` or `--minor`, respectively.
@@ -21,20 +24,24 @@ Homebrew release:
 If this is a major or minor release (e.g. X.0.0 or X.Y.0) then there are a few more steps:
 
 1. Before creating the tag you should delete any `odisabled` code, make any
-   `odeprecated` code `odisabled` and add any new `odeprecations` that are
-   desired.
+   `odeprecated` code `odisabled`, uncomment any `# odeprecated` code and add
+   any new `odeprecations` that are desired.
 2. Write up a release notes blog post to <https://brew.sh>
    e.g. [brew.sh#319](https://github.com/Homebrew/brew.sh/pull/319).
-   This should use `brew release-notes` as input but have the wording adjusted
-   to be more human readable and explain not just what has changed but why.
+   This should use the output from `brew release [--major|--minor]` as input but
+   have the wording adjusted to be more human readable and explain not just what has changed but why.
 3. When the release has shipped and the blog post has been merged, tweet the
    blog post as the [@MacHomebrew Twitter account](https://twitter.com/MacHomebrew)
    or tweet it yourself and retweet it with the @MacHomebrew Twitter account
    (credentials are in 1Password).
-4. Send the email to the Homebrew TinyLetter email list (credentials are in
-   1Password).
-5. Consider whether to submit it to other sources e.g. Hacker News, Reddit.
-
+4. Consider whether to submit it to other sources e.g. Hacker News, Reddit.
   - Pros: gets a wider reach and user feedback
   - Cons: negative comments are common and people take this as a chance to
           complain about Homebrew (regardless of their usage)
+
+Please do not manually create a release based on older commits on the `master` branch.
+It's very hard to judge whether these have been sufficiently tested by users or if they will
+cause negative side-effects with the current state of Homebrew/homebrew-core.
+If a new branch is needed ASAP but there are things on `master` that cannot be released yet
+(e.g. new deprecations and you want to make a patch release) then revert the relevant PRs,
+follow the process above and then revert the reverted PRs to reapply them on `master`.