Display commit in package description, if available (Bug#28637)

MELPA includes a :commit field in its
packages (https://github.com/melpa/package-build/pull/6).  You can use
this to tell if MELPA has processed a recently-merged change.  This
commit adds that metadata to the package description buffer.

* lisp/emacs-lisp/package.el: Display commit in package description.

Copyright-paperwork-exempt: yes

1 files changed, 3 insertions, 0 deletions

diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index 8b101c1323c..dd05c70dc8e 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -2260,6 +2260,7 @@ Otherwise no newline is inserted."
          (archive (if desc (package-desc-archive desc)))
          (extras (and desc (package-desc-extras desc)))
          (homepage (cdr (assoc :url extras)))
+         (commit (cdr (assoc :commit extras)))
          (keywords (if desc (package-desc--keywords desc)))
          (built-in (eq pkg-dir 'builtin))
          (installable (and archive (not built-in)))
@@ -2332,6 +2333,8 @@ Otherwise no newline is inserted."
     (and version
          (package--print-help-section "Version"
            (package-version-join version)))
+    (when commit
+      (package--print-help-section "Commit" commit))
     (when desc
       (package--print-help-section "Summary"
         (package-desc-summary desc)))