fetch: align all "remote -> local" output

We do align "remote -> local" output by allocating 10 columns to
"remote". That produces aligned output only for short refs. An extra
pass is performed to find the longest remote ref name (that does not
produce a line longer than terminal width) to produce better aligned
output.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5510-fetch.sh

@@ -688,4 +688,19 @@ test_expect_success 'fetching with auto-gc does not lock up' '
 	)
 '
 
+test_expect_success 'fetch aligned output' '
+	git clone . full-output &&
+	test_commit looooooooooooong-tag &&
+	(
+		cd full-output &&
+		git fetch origin 2>&1 | \
+			grep -e "->" | cut -c 22- >../actual
+	) &&
+	cat >expect <<-\EOF &&
+	master               -> origin/master
+	looooooooooooong-tag -> looooooooooooong-tag
+	EOF
+	test_cmp expect actual
+'
+
 test_done