cleanup: trim trailing whitespace (#11136)

* cleanup: trim trailing whitespace

* update(`.editorconfig`)

---------

Co-authored-by: syuilo <Syuilotan@yahoo.co.jp>

packages/backend/src/server/api/endpoints/admin/announcements/update.ts

@@ -47,7 +47,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> {
 				title: ps.title,
 				text: ps.text,
 				/* eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing -- 空の文字列の場合、nullを渡すようにするため */
-				imageUrl: ps.imageUrl || null, 
+				imageUrl: ps.imageUrl || null,
 			});
 		});
 	}