Hello Philip and Emacs maintainers,

I’m submitting this patch to enhance `describe-package` by adding
information about the currently activated package and improving the
built-in version check.  Since "Other versions" already displays the
current version of the package, I’ve added an "activated" marker to
indicate which version is active in the current Emacs session.

This patch for `package.el` introduces two improvements:

1. Built-in version check: The package menu now compares the built-in
version of a package with the available version.  If the available
version is newer, the status is set to "available"; otherwise, it is
marked as "built-in".  This helps users identify when updates are
available for built-in packages.

2. Activated packages in "Other versions": Packages listed in the
"Other versions" section are now marked with ", activated" if they are
currently active in the Emacs session.  This makes it clear which
versions are in use.

I’d appreciate your feedback and suggestions for installing this patch
into the master branch.

Best regards,
David D.