enhance(frontend): Playの説明欄にMFMを使えるように (#12899)

* (enhance) Playの説明欄にMFMを使えるように

* Update Changelog

* use class for mfm component

* Update packages/frontend/src/pages/flash/flash-edit.vue

Co-authored-by: 1Step621 <86859447+1STEP621@users.noreply.github.com>

* Update flash.vue

* Update CHANGELOG.md

---------

Co-authored-by: 1Step621 <86859447+1STEP621@users.noreply.github.com>

packages/frontend/src/pages/flash/flash-edit.vue

@@ -11,7 +11,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 			<MkInput v-model="title">
 				<template #label>{{ i18n.ts._play.title }}</template>
 			</MkInput>
-			<MkTextarea v-model="summary">
+			<MkTextarea v-model="summary" :mfmAutocomplete="true" :mfmPreview="true">
 				<template #label>{{ i18n.ts._play.summary }}</template>
 			</MkTextarea>
 			<MkButton primary @click="selectPreset">{{ i18n.ts.selectFromPresets }}<i class="ti ti-chevron-down"></i></MkButton>