Update EditMessage.svelte

src/lib/EditMessage.svelte

@@ -14,6 +14,8 @@
   import { getImage } from './ImageStore.svelte'
   import { getModelDetail } from './Models.svelte'
 
+  import 'katex/dist/katex.min.css'
+
   export let message:Message
   export let chatId:number
   export let chat:Chat