Fix some typo and using foreach instead of map in BoringUtils (#1755) (#1761)

If a method passed to higher function does not return any value,
it is prefer to use `foreach` instead of `map`.

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
(cherry picked from commit 654db98e

)

Co-authored-by: SoyaOhnishi <ohnishi.soya@arc.cs.okayama-u.ac.jp>