Translate "Separating Events from Effects" (#609)

* translate Reactive values and reactive logic

* translate Declaring an Effect Event

* translate Reading latest props and state with Effect Events

* translate challenges

* fixed

* Apply suggestions from code review

Co-authored-by: Soichiro Miki <[email protected]>

* ""ではなく、「」で囲うよう修正

Co-authored-by: Soichiro Miki <[email protected]>

* 一行空白が抜けていたので追加

* インタラクションを「ユーザ操作」に修正

* Add blank line

* Translate side bar

* 微修正

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Co-authored-by: Soichiro Miki <[email protected]>

Author: kotaesaki