Eli Zaretskii <eliz@gnu.org> writes:

— a/etc/NEWS
+ b/etc/NEWS
@@ -111,6 +111,10 @@ If you have been using these variables in Lisp code (for example, in
font-lock rules), simply quote the symbol, to use the face directly
instead of its now-obsolete variable.

+** New minor mode 'electric-block-comment-mode'
+This mode automatically close block comment typed, thus typing
+"" in c-mode automatically inserts "".
+

This should mention block-comment-start and block-comment-end. Also,
it would be good to name a few modes which support block comments,
just so users of those modes will become interested.

I agree, done.

Sending fixed patch.