scripts/spelling.txt: increase error-prone spell checking

Increase direcly,ununsed,manger spelling error check

Signed-off-by: Wang Qing <wangqing@vivo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Wang Qing <wangqing@vivo.com>
Cc: Xiong <xndchn@gmail.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: Jonathan Neuschfer <j.neuschaefer@gmx.net>
Cc: Luca Ceresoli <luca@lucaceresoli.net>
Cc: Joe Perches <joe@perches.com>
Link: https://lkml.kernel.org/r/1601085397-27586-1-git-send-email-wangqing@vivo.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>