fmt-merge-msg: respect core.commentchar in people credits

Commit eff80a9 (Allow custom "comment char") introduced a custom
comment character for commit messages but forgot to use it in
people credits which can be a part of a commit message.

With this commit, the custom comment character is also used
in people credits.

Signed-off-by: Ralf Thielow <ralf.thielow@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fmt-merge-msg.c

@@ -287,10 +287,10 @@ static void credit_people(struct strbuf *out,
 	const char *me;
 
 	if (kind == 'a') {
-		label = "\n# By ";
+		label = "By";
 		me = git_author_info(IDENT_NO_DATE);
 	} else {
-		label = "\n# Via ";
+		label = "Via";
 		me = git_committer_info(IDENT_NO_DATE);
 	}
 
@@ -300,7 +300,7 @@ static void credit_people(struct strbuf *out,
 	     (me = skip_prefix(me, them->items->string)) != NULL &&
 	     skip_prefix(me, " <")))
 		return;
-	strbuf_addstr(out, label);
+	strbuf_addf(out, "\n%c %s ", comment_line_char, label);
 	add_people_count(out, them);
 }
 

t/t6200-fmt-merge-msg.sh

@@ -180,6 +180,24 @@ test_expect_success 'merge.log=5 shows all 5 commits' '
 	test_cmp expected actual
 '
 
+test_expect_success '--log=5 with custom comment character' '
+	cat >expected <<-EOF &&
+	Merge branch ${apos}left${apos}
+
+	/ By Another Author (3) and A U Thor (2)
+	/ Via Another Committer
+	* left:
+	  Left #5
+	  Left #4
+	  Left #3
+	  Common #2
+	  Common #1
+	EOF
+
+	git -c core.commentchar="/" fmt-merge-msg --log=5 <.git/FETCH_HEAD >actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'merge.log=0 disables shortlog' '
 	echo "Merge branch ${apos}left${apos}" >expected
 	git -c merge.log=0 fmt-merge-msg <.git/FETCH_HEAD >actual &&