object-name: show date for ambiguous tag objects

Make the ambiguous tag object output nicer in the case of tag objects
such as ebf3c04 (Git 2.32, 2021-06-06) by including the date in
the "tagger" header. I.e.:

    $ git rev-parse b7e68
    error: short object ID b7e68 is ambiguous
    hint: The candidates are:
    hint:   b7e68c4 tag 2021-06-06 - v2.32.0
    hint:   b7e68ae18e0 commit 2019-12-23 - bisect: use the standard 'if (!var)' way to check for 0
    hint:   b7e68f6 tree
    hint:   b7e6849 blob
    b7e68
    [...]

Before this we'd emit a "tag" line without a date, e.g.:

    hint:   b7e68c4 tag v2.32.0

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: avar

object-name.c

@@ -408,19 +408,24 @@ static int show_ambiguous_object(const struct object_id *oid, void *data)
 			 * TRANSLATORS: This is a line of ambiguous
 			 * tag object output. E.g.:
 			 *
-			 *    "deadbeef tag Some Tag Message"
+			 *    "deadbeef tag 2022-01-01 - Some Tag Message"
 			 *
-			 * The second argument is the "tag" string
+			 * The second argument is the YYYY-MM-DD found
+			 * in the tag.
+			 *
+			 * The third argument is the "tag" string
 			 * from object.c.
 			 */
-			strbuf_addf(&desc, _("%s tag %s"), hash, tag->tag);
+			strbuf_addf(&desc, _("%s tag %s - %s"), hash,
+				    show_date(tag->date, 0, DATE_MODE(SHORT)),
+				    tag->tag);
 		} else {
 			/*
 			 * TRANSLATORS: This is a line of ambiguous
 			 * tag object output where we couldn't parse
 			 * the tag itself. E.g.:
 			 *
-			 *    "deadbeef tag [bad tag, could not parse it]"
+			 *    "deadbeef [bad tag, could not parse it]"
 			 */
 			strbuf_addf(&desc, _("%s [bad tag, could not parse it]"),
 				    hash);