Reacting to input with state翻訳 (#571)

* Translate "Reacting to Input with State" under "Managing State"

* Fix translation of "visual states" in "Reacting to Input with State"

* fix "Step 3: Represent the state in memory with useState"

* 「訳語の統一」と「翻訳ガイド」に従い、訳語を修正しました。

* Apply suggestions from code review

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

* Apply suggestions from code review

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

* Remove undesirable space

* Update sidebar

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

Author: youliangdao