fix mistakes related with font effect
fix mistakes related with font effect

1. font effected text using special marker like backtick(`) or
underbar(_) should have blank between the marked text and
neighboring word.

2. space inside font effected text should use the special marker rather
than real space.

Some mistakes were made by not fit the rules above and it displayed
unnecessary special marker characters in result paper. Fix those trivial
mistakes.

Signed-off-by: SeongJae Park <4e244449b52bf6ddddd07d261eea0e61e60df45e@gmail.com>

atomaths/go-tour-translator,atomaths/go-tour-translator