pull: colorize the hint about setting `pull.rebase`

In d18c950a69 (pull: warn if the user didn't say whether to rebase or
to merge, 2020-03-09), a new hint was introduced to encourage users to
make a conscious decision about whether they want their pull to merge or
to rebase by configuring the `pull.rebase` setting.

This warning was clearly intended to advise users, but as pointed out in
https://lore.kernel.org/git/87ima2rdsm.fsf%40evledraar.gmail.com, it
uses `warning()` instead of `advise()`.

One consequence is that the advice is not colorized in the same manner
as other, similar messages. So let's use `advise()` instead.

Pointed-out-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/pull.c

@@ -345,7 +345,7 @@ static enum rebase_type config_get_rebase(void)
 		return parse_config_rebase("pull.rebase", value, 1);
 
 	if (opt_verbosity >= 0 && !opt_ff) {
-		warning(_("Pulling without specifying how to reconcile divergent branches is\n"
+		advise(_("Pulling without specifying how to reconcile divergent branches is\n"
 			 "discouraged. You can squelch this message by running one of the following\n"
 			 "commands sometime before your next pull:\n"
 			 "\n"

t/t7601-merge-pull-config.sh

@@ -29,8 +29,11 @@ test_expect_success 'setup' '
 
 test_expect_success 'pull.rebase not set' '
 	git reset --hard c0 &&
-	git pull . c1 2>err &&
+	git -c color.advice=always pull . c1 2>err &&
-	test_i18ngrep "Pulling without specifying how to reconcile" err
+	test_decode_color <err >decoded &&
+	test_i18ngrep "<YELLOW>hint: " decoded &&
+	test_i18ngrep "Pulling without specifying how to reconcile" decoded
+
 '
 
 test_expect_success 'pull.rebase not set and pull.ff=true' '