fix(ProseA): prop types mismatch

src/runtime/components/prose/ProseA.vue

@@ -8,13 +8,15 @@
 </template>
 
 <script setup lang="ts">
+import type { PropType } from 'vue'
+
 defineProps({
   href: {
     type: String,
     default: ''
   },
   target: {
-    type: String,
+    type: String as PropType<'_blank' | '_parent' | '_self' | '_top' | (string & {}) | null | undefined>,
     default: undefined,
     required: false
   }