some moar i18n

Signed-off-by: Marcin Mikołajczak <me@m4sk.in>

src/client/app/mobile/views/components/sub-note-content.vue

@@ -1,7 +1,7 @@
 <template>
 <div class="mk-sub-note-content">
 	<div class="body">
-		<span v-if="note.isHidden" style="opacity: 0.5">(この投稿は非公開です)</span>
+		<span v-if="note.isHidden" style="opacity: 0.5">(%i18n:@hidden%)</span>
 		<a class="reply" v-if="note.replyId">%fa:reply%</a>
 		<mk-note-html v-if="note.text" :text="note.text" :i="$store.state.i"/>
 		<a class="rp" v-if="note.renoteId">RP: ...</a>