translating style-guide: Priority A (#398)
translating style-guide: Priority A (#398)

* Translated from:"Multi-word component names" to:"Prop definitions"

* fixed Typo

* レビュー指摘箇所を修正

* translated keyed v-for

* translated 'Component style scoping' n 'Private property names'

* 指摘箇所修正

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