HowToReleaseLLVM: Add some more details about website updates

[thieta]

LGTM

llvm/docs/HowToReleaseLLVM.rst

#. Copy and commit the ``llvm/docs`` and ``LICENSE.txt`` files into this new
    directory.
 
 #. Update the ``releases/download.html`` file with links to the release
    binaries on GitHub.
 
 #. Update the ``releases/index.html`` with the new release and link to release
    documentation.
 
+#. After you push the changes to the www-releases repo, someone with admin
+   access must login to prereleases-origin.llvm.org and manually pull the new
+   changes into /data/www-releases/.  This is where the website is served from.
+
 #. Finally checkout the llvm-www repo and update the main page
    (``index.html`` and sidebar) to point to the new release and release
    announcement.
 
 Announce the Release
 ^^^^^^^^^^^^^^^^^^^^
 
-Send an email to the list announcing the release, pointing people to all the
-relevant documentation, download pages and bugs fixed.
+Create a new post in the `Announce Category<https://discourse.llvm.org/c/announce>`_
+once all the release tasks are complete.  For X.0.0 releases, make sure to include a
+link to the release notes in the post.  For X.0.1+ releases, generate a changelog
+using this command and add it to the post.
+
+::
+
+  $ git log --format="[%h %s](https://github.com/llvm/llvm-project/commit/%H)" llvmorg-X.0.N-1..llvmorg-X.0.N
+
+Once the release has been announced add a link to the announcement on the llvm
+homepage (from the llvm-www repo) in the "Release Emails" section.