japanese/yc.el: Adapt to newer emacs versions

The "process-kill-without-query" function was made
obsolete in emacs 27.1 [1]. Therefore the function
should be replaced in japanese/yc.el by
"set-process-query-on-exit-flag" function.

[1] http://git.savannah.gnu.org/cgit/emacs.git/commit/?id=f1c48b0

PR: 249873
Submitted by: Takayuki Nakao <t@nakao.org> (maintainer)
Approved by: tcberner (mentor)
Differential Revision: https://reviews.freebsd.org/D27473