docs/memory-barriers.txt.kokr: Minor wordsmith

docs/memory-barriers.txt.kokr: Minor wordsmith

As suggested by Paul, I got a review from another Korean hacker Yunjae.
 From the review, I got not only 'Reviewed-by:' tags, but also found a
few minor nits.  So I made a second version of the patchset but just
realized that the first version has already sent to Linus.  I therefore
send only the nit fixes as another patch.

----------------------------- >8 ----------------------------------------
docs/memory-barriers.txt.kokr: Minor wordsmith

This commit fixes a couple of minor nits in the Korean translation of
'memory-barriers.txt'.

Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Yunjae Lee <lyj7694@gmail.com>
Link: https://lore.kernel.org/r/20191129182823.8710-1-sjpark@amazon.de
Signed-off-by: Jonathan Corbet <corbet@lwn.net>