Documentation/translation: Use Korean for Korean translation title

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Link: https://lore.kernel.org/r/20191121234125.28032-7-sj38.park@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/translations/ko_KR/index.rst

@@ -3,8 +3,8 @@
         \renewcommand\thesection*
         \renewcommand\thesubsection*
 
-Korean translations
-===================
+한국어 번역
+===========
 
 .. toctree::
    :maxdepth: 1