[FIX] change the display name of Korean to KR in the switcher

According to feedback from our Korean translator,the abbreviation for
Korean is usually KR instead of KO.

This commit updates the name of the language as displayed in the
language switcher.

closes odoo/documentation#10791

X-original-commit: 1725552c89
Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>
Signed-off-by: Louis Wicket (wil) <wil@odoo.com>

conf.py

@@ -253,7 +253,7 @@ languages_names = {
     'fr': 'FR',
     'it': 'IT',
     'ja': 'JA',
-    'ko': 'KO',
+    'ko': 'KR',
     'nl': 'NL',
     'pt_BR': 'PT',
     'ro': 'RO',