fix: compiler warnings

see:
- https://v3.vuejs.org/guide/migration/key-attribute.html
- https://v3.vuejs.org/guide/migration/v-bind.html
- https://v3.vuejs.org/guide/migration/v-on-native-modifier-removed.html

src/components/misc/notification.vue

@@ -11,7 +11,7 @@
 			>
 				<div v-if="item.title" class="notification-title">{{ item.title }}</div>
 				<div class="notification-content">
-					<template v-for="(t, k) in item.text">{{ t }}<br :key="k"/></template>
+					<template v-for="(t, k) in item.text" :key="k">{{ t }}<br /></template>
 				</div>
 				<div
 					class="buttons is-right"

src/components/misc/shortcut.vue

@@ -1,8 +1,8 @@
 <template>
 	<span class="shortcuts">
-		<template v-for="(k, i) in keys">
-			<kbd :key="i">{{ k }}</kbd>
-			<span v-if="i < keys.length - 1" :key="`plus${i}`">+</span>
+		<template v-for="(k, i) in keys" :key="i">
+			<kbd>{{ k }}</kbd>
+			<span v-if="i < keys.length - 1">+</span>
 		</template>
 	</span>
 </template>